Three CD’s are bought at an average cost of $15 each. If a fourth CD is purchased, the average cost becomes $16. What is the cost of the fourth CD?
+36915 Average of 3 = $ 15
so price is 3*15 = $ 45 then add x
3*15 + x and divide by 4 to get the average = $ 16
(3*15 +x)/4 = 16
solve for x = $ 19
