anna needs at least $1000 to pay her bills this week. she has $250 in the bank and makes $15 an hour at her job. how many hours does she have to work thus week in order to pay her bills​

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?

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?