Saved Bookmarks
| 1. |
4 men and 8 boys can build a wall in 5 days, whereas 2 men and 6 boys can build a same wall in 8 days. In how many days can the same wall be built by 2 men and 4 boys1. 8 days2. 10 days3. 12 days4. 16 days |
|
Answer» Correct Answer - Option 2 : 10 days Given: 4 men + 8 boys, build a wall in 5 days 2 men + 6 boys, build a wall in 8 days. Formula Used: (m1 × d1 × t1 × e1/w1 × c1) = (m2 × d2 × t2 × e2/w2 × c2) m = number of men required to complete the work d = number of days required to complete the work t = time used for work in a single day e = efficiency of man w = amount of work c = consumption of a man Calculation: Using the above formula, ⇒ (4m + 8b) × 5 days = (2m + 6b) × 8 days ⇒ 20m + 40b = 16m + 48b ⇒ 20m – 16m = 48b – 40b ⇒ 4m = 8b ⇒ m : b = 2 : 1 The efficiency of a Man and a Boy is 2, and 1 respectively. Now the same wall built by 2 men and 4 boys Let the number of days required be x days ⇒ (4m + 8b) × 5 days = (2m + 4b) × x ⇒ {4(2) + 8(1)} × 5 = {2(2) + 4(1)} × x ⇒ (8 + 8) × 5 = (4 + 4) × x ⇒ x = (16 × 5)/8 ⇒ x = 10 ∴ The number of days taken by 2 men and 4 boys to build the same wall is 10 days. |
|