Robin has a collection of dimes, nickels and quarters. He has 4 times as many dimes as nickels. He has 20 more quarters than nickels. The ratio of the number of dimes to the number of quarters is 3:2. Which equation can be used to calculate the number of nickels, n, Robin has?

When george started his current job, his employer told him that at the end of the first year, he would receive two vacation days. after each year worked, his number of vacation days will double up to five work weeks (25days) of payed vacation. how many vacation days will he have in 4 years