A cistern can be filled by pipes A, X in 3 minutes 45 seconds. If the larger pipe takes 4 minutes less than the smaller pipe to fill the cistern, how much time will the smaller pipe take to fill the tank? Choose the correct answer:
A) 12min	B) 6min	C) 10min	D) 8min	E) 9min
let A is larger pipe and X is smaller then,   let time taken to X = t   then time taken to A= t-4   so efficiency of X=t-4   and efficiency of A=t   using formula time= total work/total efficiency   total work =t(t-4)   total time= 3 + 45/60= 15/4   using formula   15/4=t(t-4)/(t+t-4)   by solving it   t=10 min   so smaller pipe take 10 mins.   ANSWER:10min
<result>C</result>
A cistern can be filled by pipes A, X in 3 minutes 45 seconds. If the larger pipe takes 4 minutes less than the smaller pipe to fill the cistern, how much time will the smaller pipe take to fill the tank?