Answer - A
Explanation
A's 1 day work= 1/8, B`s 1 day work = 1/10
∴ (A+B) 1 day work = (1/8+1/10) = 9/40
Both cooperating can complete it in 40/9 days.
Answer - C
Explanation
(A+B)'s 1 day work = 1/12, A's 1 day work =1/30
∴ B's 1 day work = (1/12-1/30) = 3/60 = 1/20
Henceforth, B alone can dive the trench in 20 days.
Q 3 - A can do a bit of work in 25 days which B can complete in 20 days. Both together labor for 5 days and afterward A leaves off. How long will B take to complete the remaining work?
A - 7 days
B - 8 days
C - 9 days
D - 11 days
Answer - D
Explanation
(A+B)'s 5 days work = 5(1/25+1/20) = (5*9/100) = 9/20
Remaining work = (1-9/20) = 11/20
1/20 work is finished by B in 1 day
11/20 work is finished by B in (1*20*11/20) = 11 days
Answer - A
Explanation
(A+B)'s 1 day work = 1/12,
(B+C)'s 1 day work = 1/15,
(C+A)'S 1 day work = 1/20
Including: 2(A+B+C)'s 1 day work = (1/12+ 1/15+ 1/20)= 12/60 = 1/5
∴ (A+B+C) `s 1 day work = (1/2 *1/5) = 1/10
∴ working together they can complete the work in 10 days.
A's 1 day work = (1/10-1/15) = 1/30, B`s 1 day work = (1/10-1/20) = 1/20
C's 1 day work = (1/10-1/12) = 1/60
∴ A alone can take the necessary steps in 30 days.
Q 5 - A can fabricate a divider in 30 days , while B alone can assemble it in 40 days, If they construct it together and get an installment of RS. 7000, what B's offer?
A - 2000
B - 3000
C - 4000
D - 6500
Answer - B
Explanation
A's 1 days work = 1/30,
B's 1 day work = 1/40,
Proportion of their shares = 1/30:1/40 = 4:3
B's offer = (7000*3/7) = Rs. 3000
Answer - B
Explanation
(A+B)'s 5 days work = 5(1/10+ 1/15)= (5* 1/6)= 5/6
Remaining work = (1-5/6) = 1/6
C's 2 days work = 1/6
(A's 5 day work): (B's 5 day work): (C's 2 days work)
= 5/10: 5/15: 1/6
= 15: 10:5 = 3:2:1
A's offer = (4500*3/6) = Rs. 2250
B's offer = (4500*2/6) = Rs. 1500
C's share= (4500*1/6) = Rs. 750
