Answer:
34²/7
Step-by-step explanation:
Take the dam to be a take and the exit of the dam to be a tap at the bottom which is used to empty the tank and the river to be a pipe at the top of the tank that is used to fill the tank
The tap takes 16 week to empty the tank how much will it empty in 1 week =¹/16
The pipe takes 30 week to fill the tank how much will it fill in 1 week =¹/30
¹/16-¹/30= ?
Get the LCM of the denominator which is 240
The fractions are now
15/240-⁸/240=⁷/240
1week=⁷/240 empty
? = 240/240 empty
Cross multiple
240/240×1÷7/240
240/240×1÷240/7=240/7
7÷240=34²/7 weeks