David invested $220 in a savings account that offers a 3% return on the investment. how many years will the value of david's investment will reach at least $400 ?

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Sarah took the advertising department from her company on a round trip to meet with a potential client. including sarah a total of 11 people took the trip. she was able to purchase coach tickets for $280 and first class tickets for $1280. she used her total budget for airfare for the trip, which was $6080. how many first class tickets did she buy? how many coach tickets did she buy?

Adele is five years older than timothy. in three years, timothy will be 2/3 of adele’s age. what is adele‘s current age?