What is the value of the expresion?

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

Franklin is purchasing a home for $82,107 and is financing 80% of it. the documentary stamp tax on the deed in his state is $0.70 per $100 or portion thereof. how much will he pay for the documentary stamp tax?

Find the input (x) of the function y=-4/3x+20 if the output (y) is -80