Subhash can copy 50 pages in 10 h, Subhash and Prakash can copy 300 pages in 40 h. In how much time can Prakash copy 30 pages? [SSC (CGL) 2014] |
A) 12 h
B) 9 h
C) 13 h
D) 10 h
Correct Answer: A
Solution :
Given, number of pages copied by Subhash in 10 h = 50 |
\[\therefore \]Number of pages copied by |
Subhash in one hour \[=\frac{50}{10}=5\]pages |
Now, number of pages copied by Subhash and |
Prakash in one hour |
\[=\frac{300}{40}=\frac{15}{2}\text{pages}\] |
Let time taken by Prakash to copied 30 pages = x h |
\[\therefore \]Number of pages copied by Prakash in one hour \[=\frac{30}{x}\] |
Now, according to the question, |
\[\frac{30}{x}+5=\frac{15}{2}\] |
\[\Rightarrow \]\[\frac{30}{x}=\frac{15}{2}-5=\frac{5}{2}\] |
\[\Rightarrow \] \[\frac{30}{x}=\frac{5}{2}\] |
\[\Rightarrow \] \[x=\frac{2\times 50}{5}\] |
\[\therefore \] \[x=12\,\,h\] |
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