Answer:
20 hrs
Step-by-step explanation:
Given:-
- Time taken by gardner 1 alone, t1 = 36 hr
- Time taken by gardner 2 alone, t2 = 45 hr
Find:-
How long would it take to landscape a lawn if both Gardner's worked together
Solution:-
- We need to see that the time taken (t) to landscape a new lawn "inversely proportional" to the number of gardner working. That is more number of gardner working will take less time.
- The time taken by (n) number of gardner to complete the landscape (x) as per "inverse relationship" is given by the following formulation:
1 / x = Sum (1 / ti)
Where, i denotes the time for nth gardner.
- We have two gardner then the relationship becomes:
1 / x = 1 / t1 + 1/t2
- Solve for x:
x = (t1*t2) / (t1 + t2)
x = (45*36) / ( 45 + 36 )
x = 20 hrs
- It will take 20 hrs to landscape of lawn if two garnders work together.
