A) 11 min
B) 6 min
C) 12 min
D) 8 min
Correct Answer: B
Solution :
Part of tank filled by A in a minute \[=\frac{1}{12}\] Part of tank filled by B in a minute \[=\frac{1}{15}\] \[\therefore \]Total part filled in a minute \[=\frac{1}{12}+\frac{1}{15}=\frac{3}{20}\] \[\therefore \]Part filled in 4 mm \[=\frac{4\times 3}{20}=\frac{3}{5}\] Now, remaining part \[=1-\frac{3}{5}=\frac{2}{5}\] \[\therefore \]Greater part, more time \[\frac{1}{15}:\frac{2}{5}::1\]\[\Rightarrow \]\[\frac{x}{15}=\frac{2}{5}\therefore x=6\,\,\min \]You need to login to perform this action.
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