Question

0.11. A and B can do a piece of work in 72 days: B and C can do it in 120 days while A and C can doit in 90 days. In what time can A alone do it?

(1) 80 days
(2) 100 days
(3) 120 days
(4) 150 days
(5) None of these

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Answer 1

Answer:

Description for Correct answer:

(A + B)'s 1 day's work = 1 / 72

(B + C)'s 1 day's work = 1/120

(A + C)'s 1 day's work = 1 /90

2(A + B + C)'s 1 day's work =172+1120+190

(A + B + C)'s 1 day's work = 5+3+4360X2=12360X2=160

A's 1 day's work = (A + B + C)'s 1 day's work - (B + C)'s 1 day's work

=160−1120=2−1120=1120

A alone can finish the work in 120 days.

clearl answer is 120