A) 110 min
B) 100 min
C) 120 min
D) 90 min
Correct Answer: B
Solution :
Let the third pipe can empty the cistern in x min. Part of cistern filled in 1 min when all three pipes are opened simultaneously \[=\frac{1}{60}+\frac{1}{75}-\frac{1}{x}\] According to the question, \[=\frac{1}{60}+\frac{1}{75}-\frac{1}{x}=\frac{1}{50}\] \[\Rightarrow \] \[\frac{1}{x}=\frac{1}{60}+\frac{1}{75}-\frac{1}{50}\] \[=\frac{5+4-6}{300}=\frac{3}{300}\] \[\Rightarrow \] \[=\frac{1}{x}=\frac{3}{300}\] \[\therefore \] \[x=\frac{300}{3}=100\,\min \]You need to login to perform this action.
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