Quantity A - Time taken by X = 26 days. Efficiency ratio X : Y = 10:13 Time ratio will be opposite of efficiency ratio. Time taken by Y = 26 × (
10
13
) = 20 Time taken by both =
1
(
1
20
+
1
26
)
=
260
23
= 11.3 days Quantity B - Let total work be = 10 × 8 = 80 units (considering 1 men does 1 unit work in a day) Work done by a child in a day = 75% of 1 unit or 0.75 unit. Work done by 6 men and 6 children in a day = 6 + 6 × 0.75 = 10.5 Time =