Answer: The manager will need Thirteen workers to fill in customers order by next year.
Explanation: to calculate how many employees needed, we will calculate it in steps.
STEP 1: Find the number of customers the manager is expecting next year. Since their will be a 15% increase.
15,000 × 15% = 2250
Therefore the expected customer is
2250 + 15,000 = 17,250
STEP2: How many hours should be used to fill all customers order by next year; since it takes one and half hour to fill a customers demand.
17,250 × 1.5 = 25,875hours
STEP3: How many hours does each employee gives a customer in a year; since 2% is used for their own relaxed time.
2000 × 2% = 40hours
Therefore;
2000 - 40 = 1960hours
STEP3: How many employees will be needed to satisfy 17,250 customers; since each employee works for 1960hour and the total hours to fill all customers order is 25,875hours
25,875 ÷ 1,960 = 13.202
Therefore the manager needs 13 workers to fill in customers order.