Let's start with the information we know.
Aiden gets $85 a month
Over 7 months, he has saved (85*7 = 595) $595
He will need to have $1955 for the laptop
1955 -
Now figure out how many months he will have to spend to get 1955 - the 595 he already has (1360 is what that comes out to.) 1360 (The total he will need) / 85 (The number you get a month)
That equals 16.
It will take Aiden at his current rate of income, 16 months to save for his new computer.
--Something to remember--
If the number you come out with is a decimal, I.E. 16.2, you will need to round up to the nearest whole number unless the equation specify's. In this case, instead of 16.2 it would be 17 months
