A and B together complete same work in 15 days. if B alone do this work in 20 days than in how many days A will do this work
Answers
A will complete work in 60 days
Answer:
60 days
Step-by-step explanation:
Given :-
A and B together complete same work in 15 days. B alone do this work in 20 days.
To find :-
In how many days A will do this work ?
Solution :-
Given that
A and B together complete same work in 15 days.
Number of days taken by both A and B to complete the same work = 15 days
work completed by both A and B in one day = 1/15
B can complete the same work in 20 days
Work completed by B in one day = 1/20
Work completed by A in one day
= Work completed by both A and B in one day - Work completed by B alone in one day
= (1/15) - (1/20)
LCM of 15 and 20 = 60
= [ (1×4)-(1×3)] / 60
= (4-3)/60
= 1/60
Work completed by A in one day = 1/60
So, Total work will be completed by A alone in 60 days .
Alternative Method:-
If A and B together complete the work in X days and B can complete the same work in Y days then A will complete the same work alone in
[XY/(Y-X)] days
So we have
X = 15 days
Y = 20 days
So , (15×20)/(20-15)
=> 300/5
=> 60 days
Answer:-
A will do the same work in 60 days alone.
Used formulae :-
- If A and B together complete the work in X days and B can complete the same work in Y days then A will complete the same work alone in [XY/(Y-X)] days