? A B can do a piece of work in 12 days. While B C in 20/3 days. Work ...
Solution:
Given, A and B can do a piece of work in 12 days while B and C can do the same work in 20/3 days.
Let us assume that the total work is equal to LCM of 12 and 20/3, i.e., 20 units.
Then, A, B, and C can do the work in 20/12, 20/12, and 20/(20/3) days respectively.
Simplifying the above expressions, we get:
A can complete the work in 5/3 days.
B can complete the work in 5 days.
C can complete the work in 3 days.
Let us assume that A alone can complete the work in x days.
Now, as per the question, A, B, and C work together for 3, 4, and 7 days respectively.
Therefore, the amount of work done by them will be:
Work done by A, B, and C in 3 days = 3(5/3 + 1/5 + 1/3) = 20/3
Work done by A, B, and C in 4 days = 4(5/3 + 1/5 + 1/3) = 80/15
Work done by A, B, and C in 7 days = 7(5/3 + 1/5 + 1/3) = 140/15
Now, the remaining work will be equal to the total work minus the work done by A, B, and C in 3, 4, and 7 days respectively.
Therefore, the remaining work will be:
20 - 20/3 = 40/3 units
20 - 80/15 = 20/3 units
20 - 140/15 = 20/3 units
Now, we can find the value of x by using the remaining work and the time taken by A alone to complete the work.
So, we get:
(40/3)/x + 3(5/3) = 20
(20/3)/x + 4(5/3) = 20
(20/3)/x + 7(5/3) = 20
Solving the above equations, we get:
x = 15 days
Therefore, A alone can complete the whole work in 15 days.
Hence, the correct option is (a) 15.
? A B can do a piece of work in 12 days. While B C in 20/3 days. Work ...
Acc to ques,
(A+B)=1/12
(B+C)=3/20
A one day work=1/3
B one day work=1/4
C one day work=1/7
now,
A's 3 day work+ B's 1 day work+C's 6 day work=1
(A+B)×3+(B+C)×1+C's 6 day work=1
3/12 + 3/20 + C's 6 day work=1
C's 6 day work=1-[3/12+3/20]=6/10
C's 1 day work=6/10×1/6=1/10
C will complete whole work alone in 10 days.
then,
A-C=1/12-3/20
A=1/12-3/20+1/10
A=1/30
A alone will complete the whole work in 30 days.
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