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According to statistics, a person will devote 35 years to sleeping and watching TV.
The number of years sleeping will exceed the number of years watching TV by 17.
Over the lifetime, how many years will the person spend on each of these activities?
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It is a joke Math problem.
I will give 3 (three) different solutions to you.
Solution 1. The most simple and primitive
Let x be the number of year watching TV.
Then the number of years sleeping is (x+17).
The sum is 35 years
x + (x+17) = 35.
Simplify and find x
2x + 17 = 35
2x = 35 - 17 = 18
x = 18/2 = 9.
ANSWER. Time for watching TW is 8 years; time for sleeping is 9+17 = 26 years.
CHECK. Total time is 9 + 26 = 35 years. ! correct !
Solution 2. The most exiting and elegant
Let x be the number of year sleeping.
Let y be the number of year watching TV.
Write equations as you read the problem
x + y = 35 (1)
x - y = 17 (2)
To solve the system, add equations. You will get
2x = 35 + 17 = 52.
Hence, x = 52/2 = 26.
Thus, time sleeping is 26 years; time watching TV is 35-26 = 9 years.
You get the same answer.
Solution 3. Mental (without using equations)
When the sum (x+y) of two numbers x and y is given and their difference (x-y) is given,
then the numbers are half-sum and half difference of the given sum and the given difference
x = = = 26; y = = = 9.
Solved in three different ways, in order for you learn as much as possible.