A shirt shop has 112 orders for t-shirt designs. Three designers can make 12 shirts in 2 hours. How many designers are needed to complete the orders in 8 hours?
First way:
3 designers can make 12 shirts in 2 hours
therefore since 8=4*2 and 4*12=48
3 designers can make 48 shirts in 8 hours
therefore since 3÷3=1 and 48÷3=16
1 designer can make 16 shirts in 8 hours
therefore since 112=16*7 and 1*7=7
7 designers can make 112 shirts in 8 hours
Second way:
Use the worker-time-job formula, which is:
where
W1 = the number of workers in the first situation.
T1 = the number of time units (hours in this case) in the first situation.
J1 = the number of jobs in the first situation.
W2 = the number of workers in the second situation.
T2 = the number of time units (hours in this case) in the second situation.
J2 = the number of jobs in the second situation.
W1 = 3 W2 = the unknown quantity
T1 = 2 T2 = 8
J1 = 12 J2 = 112
reduces to and reduces to
Cross-multiply
2W2 = 14
Divide both sides by 2
W2 = 7
Answer: 7 workers.
Edwin