the sum of 3 numbers is 11

Question

the sum of 3 numbers is 11. the first number minus the second number plus the third number is 5. the first number minus the third is 1 more than the second. find the numbers.

Answer 1

A + B + C = 11

A - B + C = 5

A - C = B + 1

 

Rearrange

 

A + B + C = 11

A - B + C = 5

A - B - C = 1

 

Add first and third

 

2A = 12

A = 6

 

Add second and third

2A - 2B = 6

12 - 2B = 6

6 - 2B = 0

6 = 2B

3 = B

 

You determine C.