What’s the value of this expression 5(4+7)-(6-2)

What ia the sum if the first 7 terms of the geometric series

Sara made $253 for 11 hours of work. at the same rate how much would he make for 7 hours of work?

Sam opened a money-market account that pays 3% simple interest. he started the account with $7,000 and made no further deposits. when he closed the account, he had earned $420 in interest. how long did he keep his account open?