ID 691

Tim received the following scores in the online math tests:

80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, and 89%

What was his average (mean) score?

ID 745

A week ago, Anna's jar was filled with 100 jellybeans.

She always took the jellybeans without looking into the jar.

Today, there are 11 green and 9 red.

Estimate the number of red jellybeans she has eaten.

ID 748

A catering company places 14 people around six tables.

What is the minimum and maximum number of people sitting around 15 tables that are all linked together on at least one side? (There must only be one group; they can't be linked in pairs, for example.)

ID 1185

ID 1186

One person is chosen at random from the list.

What is the probability that his/her name includes the letter e?

ID 1254

ID 1287

John chooses one tile without looking. He counts the number of spots.

What is the most likely number of spots on his tile?

ID 1406

Eugenia earned 60, 65, 71, 79, 85 and 90 on her mathematics examinations.

If she receives a score of 82 on the seventh exam, then the average will . . .

ID 1566

ID 1576

ID 1784

The average of a set of 12 numbers is 12.

If 1, 2 and 3 are added to the set, what is the new average?

ID 1943

I placed 6 cards in a box.

Two cards are blue on both sides, two cards are green on both sides, and two cards are green on one side and blue on the other.

If the first randomly chosen card is green on one side, what is the probability that the other side is also green?

ID 1957

ID 1978

I have six poles with the length of 1, 2, 3, 4, 5 and 6 meters.

How many different ways are there to make a triangle by choosing three appropriate poles?

ID 1984

There are five traffic lights on River Avenue.

In how many ways can the lights be set so that no neighboring lights have the same color?

(We assume a traffic light sequence where only one colour is lit at a time. This would not be the case for traffic lights in the United Kingdom and some other countries.)

ID 2051

Three apples were weighed in pairs and the weights were 200, 204, and 208 grams.

What is the weight of the lightest apple?

ID 2270

ID 2275

The base of the pyramid is a square.

How many layers are there in such a pyramid, composed of 140 balls?

ID 2308

ID 2310

ID 3004

In a survey of students, 2/3 of the girls and 1/2 of the boys preferred using pens over pencils.

Girls make up 75% of the students in the school.

What percent of the students prefer using pens?

ID 3027

A bag contains six green, five gray, and four violet disks.

If two disks are drawn at random from the bag, what is the probability that they are both green?

ID 3043

ID 3118

The slice that has been eaten had 7 mushrooms on it.

What is the estimated number of mushrooms on the entire pizza?

ID 3134

In a class, 95% of the students earned A grades on the first test, 90% earned A grades on the second test, 85% on the third test, and 80% on the fourth test.

What is the smallest possible percentage of students who earned A grades on all the tests?

ID 3211

John earned an average of 90% on his five exams.

What is the lowest possible percentage score he could have received in any one of the exams?

ID 3215

On the chessboard, what is the probability that a randomly chosen square is dark and it touches the outer edge of the board?

ID 3277

ID 3370

Anna recorded the temperature every day for a week (7days).

It was 22° on Monday.

The temperature decreased by 3° every day.

What was the average temperature for the week?

ID 3435

The table shows the results of a competition among 5 teams.

How many teams received less points than the average?

ID 3447

Bob the plumber has 8 pockets and 40 nuts.

He wants to put the nuts in all of his pockets so that no two pockets have the same number of nuts.

What is the largest number of nuts that a pocket can possess?

ID 3497

Bob shaves himself 3 minutes every day including the weekends.

If he starts shaving at the age of 20 and lives 70 years, what is the total amount of time spent shaving?

ID 3503

A palindrome is a word, phrase, or sequence that reads the same backwards as forwards.

For example, 123454321 is a nine-digit palindrome.

What is the minimal difference between two nine-digit palindromes?

ID 3530

ID 3580

John owns 3/4 of a timber business and sells 2/9 of his share for $600,000.

What is the value of the business?

ID 3583

A surgeon has two pairs of surgical gloves.

What is the maximum number of people on which he is able to operate?

NOTE:

1)There is no blood contact between the people including the surgeon.

2) The surgeon needs to use both hands for each operation.

ID 3639

Arrange nine numbers in a circle so that the difference between neighboring numbers is always less than 3.

Which of the following pairs cannot be neighbors?

ID 3661

What is the average of the first 2016 counting numbers?

Counting numbers (1, 2, 3, . . .) are whole numbers (0, 1, 2, . . .), but without the zero, because you don't "count" zero.

ID 3759

Anna needs $250 to buy a music box. In January, she saved $4. She saved twice as much in February as she saved in January.

If she continues to save twice as much each month as she saved the previous month, in what month will her total savings be enough to purchase the device?

ID 3853

Maria answered 22 of the 25 questions on her test.

Half of them, she did correctly.

What is her score on the test?

ID 3958

The symbol N! denotes the product of the first N positive integers.

Find the value of N for which

(3!)(4!)(7!) = 2(N!)

ID 4285

ID 4310

Nine people stand in a queue.

The first person takes 9 apples, and each other man takes one apple less than the person before him.

The last person takes the last apple.

What percentage of the total number of apples does the first person take?

ID 4380

ID 4629

ID 4645

ID 4671

ID 4685

ID 4807

ID 4898

A bus can hold 66 students.

The bus starts out empty and picks up 1 student at the first stop, 2 students at the second stop, 3 students at the third stop, and so forth.

After how many stops will the bus be full?

ID 4922

The letters A, E, I, O, and U are vowels.

What percent of the letters in the word FACEBOOK are vowels?

ID 5162

What is the sum of dots that are not visible from the current direction, but would be visible if the tower were looked at from the other side?

The opposite sides of a standard die have numbers that add up to seven.

ID 5241

Martin saves $8 on March 1st.

Each day after that he saves $2 more than he saved the day before.

How much would he have saved by the end of the month?

ID 5283

Three brothers share their father's sheep.

Father said that the second son gets 20% less sheep than the eldest son, and the youngest son gets 20% less than the second son.

How many sheep does the eldest son get if there are 488 sheep in total?

ID 5288

ID 5499

Jane has forgotten the address of her friend’s house, but knows it contains the numbers 7 or 9.

She wants to choose one of the directions, and then recognize the house, which she visited a couple of years ago.

Which direction has more mathematical chances?

ID 5525

Gerry rolled three standard cubical dice and added up the numbers showing on the top faces.

How many different sums are possible?

ID 5563

ID 5569

Gerry used a calculator to find the difference of two positive integers, but instead of pressing the minus key (-) he pressed the plus key (+).

The answer was 9.

What should the answer have been?

ID 5571

Today is Monday. If a fortune teller predicts that you will become an Olympic Champion in 1000 days, what day of the week will it be?

ID 5577

At a school, there were forty-five ninth graders who received a mom's kiss in the morning and thirty who did not.

What percentage of the ninth graders received a mom's kiss?

ID 5609

Jane buys a chair during the sale. If the original price was $40, how much does Jane pay if it is written “Sale : 40% OFF”?

ID 5613

ID 5630

ID 5642

ID 5651

Gerry's rich uncle gave him $2 on his first birthday. On each birthday after that he doubled his previous gift.

How much did the uncle give on Gerry's tenth birthday?

ID 5677

What is the largest number of X's you can place on the 4x4 board without making four-in-a-line in any direction?

ID 5702

Ten-dollar hammers are on sale in the Cheat-Mart today.

**Buy two for the price of three and get 60% off!**

What is the final hammer price for me if I really need only one hammer?

ID 5826

ID 5831

Leslie Green asks:

"**The History of Art in the Dark Ages** is an epically boring subject and too many students pass by simply answering the 100 multiple choice exam questions randomly. This year the marking scheme has been changed so that of the 4 possible answers, the correct answer scores one point, two wrong answers score 0, but the remaining stupid answer scores minus two points.

What is the expected score for a student who guesses randomly?"

ID 5834

ID 5855

People used to work shifts lasting up to 14 hours per day, 6 days per week in the 1800's.

In 2002, the average working week was 41.5 hours in Swiss companies.

Estimate the percentage of the working time now compared to the age of the Industrial Revolution (the nineteenth century).

ID 6041

ID 6052

There are four people in a line.

If only the order of men and women matters, how many ways can they line up?

ID 6059

ID 6066

ID 6138

ID 6189

The surface area of the Earth is 510 million km^{2}. About 71 percent of the Earth's surface is water-covered.

An expert estimates that the area of the Bermuda triangle is about 2.55 million km^{2}.

What percent of the Earth's water surface is the Bermuda triangle?

ID 6197

ID 6210

In a competition "The Best Smile of the Year", twenty participants successfully failed to pass to the final stage of the competition.

This is 40% of the total number of participants.

Of course, handsome Johnny passed to the final.

How many participants passed to the final stage of the competition?

ID 6284

A small unmanned rocket program is having budget difficulties so the project director wants at least a 1% cut in the parts cost. The parts are roughly broken down as follows:

$9M Rocket Engines

$900k Avionics

$90k super-structure

$10k miscellaneous items

Which change best meets the project director’s requirements?

Author: Leslie Green

ID 6386

In the diagram on the right, certain paths correctly spell the word PUZZLE.

What is the total number of different paths for PUZZLE in the diagram?

ID 6406

The Funny Pins bowling club consists of five married couples.

The club has decided to create a mixed (man-woman) team for the next tournament by randomly selecting partners. They don't want spouses to play in the team.

How many different teams are possible?

ID 6415

Evguenia had a mean score of 80 points on five tests. One test was scored incorrectly, and its score was later raised by ten points.

What is the new mean score?

ID 6424

In a school, the size of a class is between 20 and 30 students.

If 48% of the students in a class are girls, how many boys are there in the class?

ID 6640

ID 6656

Bob is currently paid $99 for working a day.

His hourly wage is to be increased by 10% but his hours are to be reduced by 10%.

What is his new daily salary?

ID 6805

A genie has rewarded Gerry with four wishes to be executed on Gerry's money:

A: Add $1

D: Divide by 2

M: Multiply by 3

S: Subtract $4

Gerry must take all four wishes.

In which order do you advise Gerry to use these wishes?

ID 6938

ID 7027

ID 7334

Gerry had $7, Jane $18, and Kate as much as Gerry and Jane together.

They gave all their money to a Children Charity Foundation.

What was Gerry's contribution in percent?

ID 7394

A set of Mr. Greed's 5929 gold ingots can be separated into equal piles.

What is the smallest possible number of the ingots in a pile?