Q. predict and test to solve:

Two numbers have a sum of 39. Their differrence is 11. What are the two numbers?

Answers to 'predict and test to solve'
Answer 1

Let the 2 numbers be x and y.

Given that sum of 2 numbers is 39

x + y = 39 .........(1)

Difference of 2 numbers is 11

x - y = 11 .........(2)

We have 2 equations

x + y = 39

x - y = 11

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Adding these 2 equations, we get

(x+y) + (x-y) = 39 + 11

x + y + x - y = 50

2x = 50

2x/2 = 50/2

x = 25

substitute this vaue in equation (1)

x + y = 39

25 + y = 39

y = 39 - 25

y = 14

Therefore the 2 numbers are 25 and 14.

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Q.

Two numbers have a sum of 39. Their differrence is 11. What are the two numbers?

A.