Answer:
x three hours
Step-by-step explanation:
With two reapers a field can be harvested in 1 hour
Operating only the newer reaper crop can be harvested in 1,5 hour (3/2), then in one hour it does 1/(3/2) = 2/3
Let call x number of hours the older reaper, take doing the job, then
In 1 hour time the older reaper does 1 / x
Then according to problem statement
As with two reapers the field can harvested in one hour
1/ x + 2/3 = 1 ⇒ ( 3 + 2*x ) /3*x = 1
3 + 2*x = 3*x
- 3*x + 2*x = - 3
- x = -3
x = 3
