InterviewSolution
| 1. |
5 class A workers and 4 class B workers are assigned a job to paint a circular park. They work for one day and complete painting till half the radius of the circular park. The next day, class B workers go on strike and returns the day after as the management resolves their problems. This creates a delay of 4 hours and 48 min in overall. If their payment is based on their efficiency, what will be the ratio of their pay?1). 16 : 52). 5 : 163). 8 : 54). 5 : 8 |
|
Answer» Let a class A worker complete the work in ‘a’ days and a class B worker complete the work in ‘b’ days ⇒ Amount of work done by a class A worker in 1 day = 1/a ⇒ Amount of work done by a class B worker in 1 day = 1/b ⇒ Amount of work done by 5 class A and 4 class B workers in 1 day = 5/a + 4/b = 1/4 [? Half the radius, quarter the AREA of the CIRCLE] ⇒ 20/a + 16/b = 1 → 1 So, they would have completed the work in 4 days if the strike did not happen. But, it takes 4 days 4 HOURS and 48 min due to the strike Class A workers work for 4 days 4 hours 48 min whereas class B workers work for 3 days 4 hours 48 min ⇒ 4 hours 48 min = (4/24) + {48/ (60 × 24)} = 0.2 day ⇒ Total amount of work done = 4.2 × (5/a) + 3.2 × (4/a) ⇒ 1 = 21/a + 12.8/b → 2 Comparing EQUATIONS 1 and 2 ⇒ 21/a + 12.8/b = 20/a + 16/b ⇒ 1/a = 3.2/b ⇒ a/b = 1/3.2 Efficiency ∝ 1/Time taken ∴ Ratio of their efficiencies = 3.2 : 1 = 16 : 5 |
|