Question

For each of the last 3 months, Olga saved $75, $96 and $84. Which is the minimum

amount she should save next month in order to save an average of $90 for these 4 months

Answer 1

She needs to save a total of 90(4)=$360.

She has already saved 75+96+84=$255.

This means she needs to save at least 360-255=$105.