I should probably explain it, the reason for this is mainly just by dividing the fact that adding the other hose takes away 8 hours of work we can deduce that the amount of water it can put out can do it 2 times faster than the normal hose so the answer is 6
First order the numbers then cross out the numbers till in the middle the numbers 6.4 and 6.7 add then divide by two to get the middle and the median 13.1/2 =6.55