Taps A and B can fill a bucket in 10 minutes and 15 minutes respectively. If both are opened and A is closed after 3 minutes, how much further time would it take for B to fill the bucket?	Choose the correct choice.
A) 7 min. 30 sec.	B) 8min. 20 sec.	C) 7min. 25 sec	D) 7 min.35 sec.	E) 8min. 20 sec.
Explanation:   Part filled in 3 minutes =   3∗(1/10+1/15)=3∗5/30=5/10   Remaining part =1−5/10=5/10   =&gt;1/15:5/10=1:X   =&gt;X=15/2   =&gt;X=7.5mins.   So it will take further 7 mins 30 seconds to fill the bucket.   Option7 min. 30 sec.
<result>A</result>
Taps A and B can fill a bucket in 10 minutes and 15 minutes respectively. If both are opened and A is closed after 3 minutes, how much further time would it take for B to fill the bucket?