A market researcher polled every tenth person who walks into a store. What type of sampling was used

If the value of x increases by 5, how does the value of m(x + 3) change? a) it increases by 5m. b) it increases by 8m. c) it decreases by 5m. d) it decreases by 8m.

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

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab