Two pipes can fill the cistern in 10hr and 12 hr respectively, while the third empty it in 25hr. If all pipes are opened simultaneously, then the cistern will be filled in Choose the correct option: A) 7.5 hr B) 6.98 hr C) 8.5 hr D) 10 hr E) None of these
Solution:   Work done by all the tanks working together in 1 hour.   1/10+1/12−1/25=1/7   Hence, tank will be filled in 6.98 hour   Option(6.98 hr)
<result>B</result>
Two pipes can fill the cistern in 10hr and 12 hr respectively, while the third empty it in 25hr. If all pipes are opened simultaneously, then the cistern will be filled in