A alone can do a piece of work in 12 days and
B alone can do the same work in 15 days. They
start working together. After 4 days B leaves the
work. In how many days A alone complete the
remaining work?
Answers
Answer:
A alone can do the work in 12 days he can do = 1/12 work in one day
B alone can do the work in 15 days
He can do = 1/15 work in one day
A works for 4 days
Work done = 4 × 1/12 = 4/12 = 1/3
work remaining = 1 - 1/3 = 2/3
A and B together can do = 1/12 + 1/15 = (5+4)/60 = 9/60 work in 1 day.
To finish the remaining work together, they need = (2/3) ÷ (9/60) = 2/3 × 60/9 = 40/9 days = 4 4/9 days
They need 4 4/9 days to finish the work.
Answer:
ABOUT 5 days
Step-by-step explanation:
A = 1 work per 12 days
B = 1 work per 15 days
First, let's flip it around
A = 0.083 work (rounded) per 1 day
B = 0.067 work (rounded) per 1 day
Let's add up the amount of work they can do in 1 day:
0.083 + 0.067 = 0.15
So in the four days, B was around they got 0.15 x 4 work in.
0.15 x 4 = 0.6
Now there is 0.4 work left for A to do.
0.083 x _ = 0.4
Let's re-write that:
0.4/0.083 = 4.81927710843
Now, let's round the quotient to a full day
5
It will take (about) 5 days for A to complete the work