The laundromats in Sean’s new apartment complex are working on a chargeable card. Sean just got a brand new one with a $0 balance on it. The charging machine allows only a $10 charge each time. Sean charged the card with the first $10.
Each wash costs $1.75. A wash is possible when there are sufficient funds on the card. How many more $10 charges Sean has to do before an exact $0 balance is reached on the card again?
Sean has to charge 6 more times of $10 each before being able to reach the $0 balance on his card.
A faster way to calculate this is to obtain the least 10-divisible number which can be divided by 1.75 without a remainder. This is 70 (initial 10 plus 6×10). Divided by 1.75 it results in 40. This is the number of washes Sean made before reaching the $0 balance.