29. A factory producing cell phones has the following cost and revenue functions C(x) - x + 75x + 2,688 and R(x) - x + 160x. What is the range of cell phones they should produce each day so there is profit? Round to the nearest number that generates profit. )13 or more cell phones per day 2 or more cell phones per day 23 or more cell phones per day 32 or more cell phones per day