Question

Exercises

Answer 1

A)
Note that there are only two numbers that correspond complete wording of question: 59 and 68
It is easy to verify that the number found number is 68:

Look:
6 + 8 = 14 and
86 - 68 = 18

b)
Now you can solve one system:

x + y = 21
x - y = 5

Add both equations:

2x = 26
x = 13

So: y = 8