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03 Jan 2021, 04:52
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
68% (01:28) correct
32%
(01:32)
wrong
based on 96
sessions
History
Date
Time
Result
Not Attempted Yet
Machine A can produce bolts at a rate that is three times faster than that of machine B. if it takes machines A and B, working simultaneously, to produce a batch of bolts in 3 hours, then how long would it take machine B to produce the same batch of bolts?
(A) 4
(B) 6
(C) 9
(D) 12
(E) 15
(A) 4
(B) 6
(C) 9
(D) 12
(E) 15
04 Jan 2021, 03:18
Kudos
Bookmarks
Let \(A=3x\) and \(B=x\)
Follow the diagram before proceeding to the next step:
\(\frac{3x^2}{x+3x}=3\)
\(3x^2=12\)
\(x=4\)
\(A=12\)
\(B=4\)
Total Work\(=3*4^2=3*16\)
Time Taken by \(B=\frac{3*16}{4}=3*4=12\)
Ans D
Follow the diagram before proceeding to the next step:
\(\frac{3x^2}{x+3x}=3\)
\(3x^2=12\)
\(x=4\)
\(A=12\)
\(B=4\)
Total Work\(=3*4^2=3*16\)
Time Taken by \(B=\frac{3*16}{4}=3*4=12\)
Ans D
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04 Jan 2021, 08:47
Kudos
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sjuniv32
Let efficiency of A be 3 units/Hr & efficiency of B be 1 unit/Hr
So, Combined efficiency of A and B will be 4 units/Hr
Thus, Total work is 4*3 = 12 units...
Now, Time required by B to complete the job will be 12/1 = 12, Answer must be (D)
