Question

# For the same amount of work, A takes 6 hours less than B. If together they complete the work in 13 hours 20 minutes, find how much time will B alone take to complete the work? 40 hrs 10 hrs 15 hrs 30 hrs

Solution

## The correct option is D 30 hrs If B alone takes x hours then A alone takes (x - 6) hours for the same work. ∴ 1x−6+1x=340                  [ 13 hours 20 min = 403 ] →         x+x−6(x−6)x=340 →          3x2−18x=80x−240                                 3x2−98x+240=0                                 3x2−90x−8x+240=0                                 (x−30)(3x−8)=0 →   x = 30 or x = 83              Since, time can't be in fraction  ∴   B alone will take 30 hrs to complete the work.

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