A) 20
B) 25
C) 30
D) 10
Correct Answer: A
Solution :
Remaining work \[=1-\frac{37}{100}\] \[=\frac{100-37}{100}=\frac{63}{100}\] \[\therefore \] Time taken by (A + B) in doing \[\frac{63}{100}\] part of work = 7 days \[\therefore \] Time taken by them in doing whole work \[=\frac{100}{63}\times 7=\frac{100}{9}\] days Respective ratio of time taken by A and B in doing the work \[=5:4\] \[\therefore \] \[\frac{1}{4x}+\frac{1}{5x}=\frac{9}{100}\] \[\Rightarrow \] \[\frac{5+4}{20x}=\frac{9}{100}\] \[\Rightarrow \] \[20x=100\Rightarrow \,x=5\] \[\therefore \] Required time \[=4\times 5=20\] daysYou need to login to perform this action.
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