Question

Mira picked two numbers from a bowl. The difference of the two numbers was 4, and the sum of one-half of each number was 18. The system that represents Mira’s numbers is below. x – y = 4 x + y = 18

Answer 1

The sum of one-half of each number is 18, therefore 18/2=9
Solving the system below:
x-y=4
x+y=18

If you add x+x, -y+y and 4+18:
2x=22
x=11

Solving the first equation to find the value of y:
11-y=4
y=7

So 7 its under 9 and therefore its not the number we are looking for. The number must be below 11 and under 9. The number is 10