Answer:
Step-by-step explanation:
<u>Equations
</u>
The relation between the number thought by Ann (N) and the final result (R) can be expressed as
So if for example, Ann thought in the number N=12, then
If we know the value of R, it's easy to find back the value of N by solving the equation
subtracting 7 on each side
Dividing by 5
So, if Ann tells Jim that R = 52, he can guess her number is