Umesh's 5 day's work = 5 x (1/15) = 1/3
Remaining work = (1 - 1/3) = 2/3
(1/10 + 1/15) work is done by both in 1 day
∴ 2/3 work is done by both in 6 x (2/3) = 4 days

Correct Option: B

Umesh's 5 day's work = 5 x (1/15) = 1/3
Remaining work = (1 - 1/3) = 2/3
(1/10 + 1/15) work is done by both in 1 day
∴ 2/3 work is done by both in 6 x (2/3) = 4 days
Hence, the work was completed in 4 + 5 = 9 days.

Time taken by Ramesh alone = (2/3) x 4 = 8/3 days
∴ Their 1 day's work = (1/4 + 1/6 + 3/8) = 19/24.

Correct Option: D

Time taken by Ramesh alone = (2/3) x 4 = 8/3 days
∴ Their 1 day's work = (1/4 + 1/6 + 3/8) = 19/24
So, together they can finish the work in 24 /19 days, i.e., 1⁵/₁₉ days.

∵ Work of (Ram + Dilip + Shekhar) for 1 day = 1/20
and work of (Ram + Dilip) for 1 day = 1/30
∴ Work of Shekhar for 1 day = 1 / 20 - 1 / 30 = 1/60

Correct Option: A

∵ Work of (Ram + Dilip + Shekhar) for 1 day = 1/20
and work of (Ram + Dilip) for 1 day = 1/30
∴ Work of Shekhar for 1 day = 1 / 20 - 1 / 30 = 1/60
Hence, Shekhar will complete the work in 60 days.

Work completed by A + B in one day = 1/6 + 1/3 = 1/2

Correct Option: C

Work completed by A + B in one day = 1/6 + 1/3 = 1/2
∴ Time taken by A + B to complete the work = 2 days.

Work to be done by C = (1 - 7/11) = 4/11
∴ (A + B) : C = 7/11 : 4/11 = 7 : 4

Correct Option: B

Work to be done by C = (1 - 7/11) = 4/11
∴ (A + B) : C = 7/11 : 4/11 = 7 : 4
∴ C's share = Rs. 550 x (4/11) = Rs. 200