The pool is filled with water through the first pipe in 3 hours, and through the second in 4 hours. If you open both pipes

The pool is filled with water through the first pipe in 3 hours, and through the second in 4 hours. If you open both pipes at the same time, the pool will be filled with water by 70% in …

Let’s convert hours into minutes 3 hours = 180 minutes, 4 hours = 240 minutes. Then 5% of 180 min = 9 min, and 5% of 240 min = 12 min. since the filling time ratio is 4: 3, then when 1 pipe fills the pool by 40%, then 2 – by 30%. 9 * 8 = 72
12 * 6 = 72, 30% + 40% = 70%
answer 72 min