Project ForgeGeneral Aptitude
Quantitative Aptitude
GATE 2010
Medium
5 skilled workers can build a wall in 20 days; 8 semi-skilled workers can build a wall in 25 days; 10 unskilled workers can build a wall in 30 days. If a team has 2 skilled, 6 semi-skilled and 5 unskilled workers, how long will it take to build the wall?
15 days
Explanation
One skilled worker's rate = 1/(5×20)=1/100 wall/day. One semi-skilled = 1/(8×25)=1/200. One unskilled = 1/(10×30)=1/300. Team rate = 2/100+6/200+5/300 = 12/600+18/600+10/600 = 40/600 = 1/15 wall/day. Time = 15 days.
Source: GATE CS 2010 (2010)
This question is part of a 15-day revision cycle — sign in and Project Forge will bring it back the day before you'd forget it.