Can someone help me I would appreciate

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

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?

David is standing on the sixth rung of a ladder while painting his house. which expressions represent a change in david’s position of 2 rungs on the ladder? choose exactly two answers that are correct. a. 6+2 b. 6-2 c. 2x6 d. 6/2