Answer:
Below
Explanation:
A) this one is easy....twice the manpower would take 1/2 the time = 1 hr
B) this requires a bit of calculation find man-hrs required per lorry
(3 men x 2 hr )/1 lorry = 6 man hours per lorry
then: 5 men * x hr = 6 man hours
x = 6/5 hr ( 1 hr 12 min)
C) similar to B 2 men * x hr = 6 man hrs
x = 6/2 hrs = 3 hrs