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Apr 2808:00 AM PDT
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11 Nov 2020, 01:14
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plaverbach
Yes, you can make the work same so that you don't have to worry about it. But to ensure that all numbers remain integers, I would take the work to be 200 hrs (LCM of 20, 25 and 40).
A will take 20 more hrs than B working alone to do this work.
Working together the work is done in 24 hrs.
1/A + 1/(A-20) = 1/24
From here, we will get time taken by A to make 200 widgets.
Options give us time taken by A to make 40 widgets. So we will check each option multiplied by 5 in our equation.
If you plug in (E) * 5 = 12*5 = 60 in the equation, you get
1/60 + 1/40 = 1/24 which is correct.
04 Sep 2025, 04:18
Kudos
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Hi KarishmaB I have a doubt in selecting the number for denominator as well.
We have 40/x + 40/(x-4) = 25/3 , we need a value of x such that we can get a 3 in the denominator but every ans opt other than 5 will give us that:
6 will give x = 6 and x-4 = 2, with LCM = 6 (multiple of 3)
8 will give x=8 & x-4 = 4 with LCM = 24 (multiple of 3)
10 will give x = 10 & x-4 = 6, LCM = 60 (multiple of 3)
12 will give x = 12 & x-4 = 8, LCM= 24 (multiple of 3)
so unless we put each options fully and solve, how are we supposed to narrow down the options?
We have 40/x + 40/(x-4) = 25/3 , we need a value of x such that we can get a 3 in the denominator but every ans opt other than 5 will give us that:
6 will give x = 6 and x-4 = 2, with LCM = 6 (multiple of 3)
8 will give x=8 & x-4 = 4 with LCM = 24 (multiple of 3)
10 will give x = 10 & x-4 = 6, LCM = 60 (multiple of 3)
12 will give x = 12 & x-4 = 8, LCM= 24 (multiple of 3)
so unless we put each options fully and solve, how are we supposed to narrow down the options?
KarishmaB
04 Sep 2025, 07:02
Kudos
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Simplify it fully first.
1/x + 1/(x-4) = 25/3*40
1/x + 1/(x-4) = 5/24
Possible option x = 12. No other option gives 3 and 8 as factors.
Or
Note that 25/3 = 8.something
40/x + 40/(x-4) = 25/3
If x = 6, 40/2 is much greater than 8.
If x = 8, 40/4 = 10 i.e. greater than 8
If x = 10, 40/10 + 40/6 is greater than 8
1/x + 1/(x-4) = 25/3*40
1/x + 1/(x-4) = 5/24
Possible option x = 12. No other option gives 3 and 8 as factors.
Or
Note that 25/3 = 8.something
40/x + 40/(x-4) = 25/3
If x = 6, 40/2 is much greater than 8.
If x = 8, 40/4 = 10 i.e. greater than 8
If x = 10, 40/10 + 40/6 is greater than 8
Natansha
