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Source: — Data Sufficiency |
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by raghavsarathy » Fri Jul 24, 2009 11:02 am
IMO - E

Machine X = y+2 days
Machine Y = y days

Machine X in one day can produce w/(y+2) and machine Y can produce w/y

Given 3w/(y+2) + 3w/y = 5/4w

Solve this for y

We end up with a quadratic eqn 5y^2 - 14y - 24=0

Solving this y = 4

Hence Machine X takes 6 days to produce w widgets

Hence to produce 2w widgets Machine X takes 12 days
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by prindaroy » Fri Jul 24, 2009 11:17 am
Agree with above;

x = d, y = d+2

To produce w widgets together it will take them; d(d+2)/2d+2

5/4w = 3, therefore w = 2.4 days

Therefore;

d(d+2)/2d+2 = 2.4

so, d^2 - 2.8d - 4.8 = 0

d(d-4) + 1.2(d-4) = 0, d = -1.2, or d = 4. therefore d = 4

x = 4, x + 2 = 6 days for w widgets. for 2w, = 2*6 = 12

So E
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