Question

please solve it fast ​

Answer 1

Answer:

7.5hr

Step-by-step explanation:

the time taken to fill 3hr

the work done in 1hr = 1/3

waste pipe time taken to empty =5hr

so work done in 1 HR = 1/5

by working together at a time = 1/3-1/5 = (5-3)/15

= 2/15

so in 15/2 hours it can fill the tap

7.5hr

Answer 2

$first \: tab \: fill \: the \: cistern \: in \: one \: hour = \frac{1}{3} \\ second \: tab \: empty \: the \: cistern \: in \: one \: hour = \frac{1}{5} \\ citern \: fill \: in \: one \: hour = \frac{1}{3} - \frac{1}{5} = \frac{2}{15} \\ the \: time \: when \: cisterm \: is \: full = \frac{15}{2} hour \: or7 .5 \leqslant hour \: or \: 7 \: hour \: 30 \: minut$