Question: Andrew works in a company that provides a generous vacation allotment: for every 10 days worked, you get 1 vacation day. If last year Andrew worked 300 days and took 5 days off in March and twice as many in September, how many more vacation days can Andrew still take?
Solution:
If for every 10 days worked Andrew earns 1 day of vacation, then over 300 days worked he would have earned 300/10=30 days of vacation
We know he took 5 days off in March and that in September twice as much. That means in September he took 5*2=10 days off
In total, Andrew has used 5 vacation days in March and another 10 in September. Therefore, he has used 5+10=15 vacation days
If Andrew earned 30 days of vacation but has only used 15, then he can still take another 30-15=15 days off
Answer: 15