Need help understanding this problem.​

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

Which of the following represents the factorization of the trinomial below? x^2+7x-30

Sally deposited money into a savings account paying 4% simple interest per year.the first year,she earned $75 in interest.how much interest will she earn during the following year?