Let x be the average airspeed of the plane. Let y be the average wind speed. Initial trip: 18 = (x + y) Return trip: 18 = (x – y) Dalia had an average airspeed of miles per hour. The average wind speed was miles per hour.

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