Created by Inna Shapiro ©2008 ! !
Created by Inna Shapiro ©2008 ! Problem 1 Two friends played chess for three hours. For how long did each of them play?
Mar 27, 2015
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Created by Inna Shapiro ©2008
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Problem 1
Two friends played chess for three hours.
For how long did each of them play?
Answer
Each of them played for three hours.
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Problem 2
A cart driven by three horses in one harness made 15 miles in 2 hours.
What was the average speed of a single horse in the harness?
Answer
The average speed of each horse was 7.5 mph.
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Problem 3
A train from Boston to New York departs exactly at 12 PM. An average speed of this train is 45 mph. At the same time the second train departs from New York to Boston. An average speed of the second train is 65 ml/hr.
When the trains pass each other somewhere midway, which one is closer to Boston?
Answer
Both trains are at the same distance to Boston at the meeting point.
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Problem 4
John and Mary Smith have five sons. Each of the sons has one sister. How many children are there in the family?
Answer
Six.
John and Mary Smith have five sons and one daughter.
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Problem 5
A carpenter has to saw each of 15 logs into 6 equal parts.
How many saw cuts should be done?
Answer
Seventy five.
In order to saw one log into 6 equal parts a carpenter has to do five saw cuts.
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Problem 6
It takes the elevator 30 seconds to get to the 6th floor.
How long would it take to get to the 2nd floor on the same elevator?
Answer
Six seconds.
It takes five times longer to get to the 6th floor than to the 2nd floor.
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Problem 7
In order to buy a book John has to pay $10 plus one half of the book’s price.
How much does the book cost?
Answer
The book costs $20.
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Problem 8
Peter wrote a legitimate expression:
35 + 10 – 45 = 42 + 12 – 54.
Then he rewrites it as
5 * (7 + 2 – 9) = 6 * (7 + 2 - 9).
Then he noticed equal expressions in parentheses and reduced both parts by this expression.
He got 5 = 6. Where did he make a mistake?
Answer
(7+2-9)=0
Peter cannot reduce both parts by 0.
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Problem 9
Is it possible to have five weekends in one month?
AnswerOf course, it is possible. For example :
The 1st weekend falls on the 1st and the 2d days of the month;
The 2d weekend falls on the 8th and the 9th days of the month;
The 3d weekend falls on the 15st and the 16d days of the month;
The 4th weekend falls on the 22d and the 23d days of the month;
The 5th weekend falls on the 29th and the 30th days of the month.
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Problem 10
Harry said: ‘The day before yesterday I was 10 years old. The next year I will celebrate my 13th birthday.
Is it possible? If so, when is Harry’s birthday?
Answer
Yes, it is possible, but only if Harry’s birthday is December 31st .
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