Philips is a leading health technology company in improving consumers’ health and home care. One of its most popular products is LED lights, designed to provide a safer light source. A hardware store sells the lights on an average of 35 units per day with the standard deviation of 2.1 units. Assume the number of unit sold for Philips LED is normally distributed.

a. What is the probability that the hardware store is selling more than 40 units of the LED lights per day?

b. What is the probability that the hardware store is selling not more than 32 units of the LED lights per day?

c. How many units need to be sold to achieve 90% of daily average sales of the LED lights in the hardware store?