Question

45. Ram and Arjun can do a piece of work in
10 days. Arjun and Rahim can do it in
12 days and Ram and Rahim can do it in
20 days. Then Ram alone can do that
piece of work in
(1)
30 days
(2)
20 days
(3)
12 days
(4)
10 days​

Answer 1

answer : 96 DAYS

Let the rates of A, B and C be a, b, and c respectively.

A and B can do a piece of work in 10 days: a + b = 1/10;

B and C can do the same work in 15 days: b + c = 1/15;

C and A can do the same work in 25 days: c + a = 1/25.

Sum the above 3 equations: 2(a + b + c) = 31/150 --> a + b + c = 31/300

Subtract a + b = 1/10 from above to get c = 1/300.

For 4 days all 3 worked and completed 4*(a + b + a) = 124/300 of the work.

For the next 4 days B and C worked and they completed 4(b + c) = 4/15 = 80/300 of the work.

So, by the time C is left alone 1 - (124/300 + 80/300) = 96/300 of the work is left to be completed by C alone.

Time = Job/Rate = (96/300)/(1/300) = 96 days.

Answer 2

Answer:

30 days

Step-by-step explanation:

first find the one day work done by all three

then subtract one day work of arjun + rahim to get the one day work of ram