How would you solve these work word problems?

Question

1. a pipe can fill a swimming pool in 10 hr. if a second pipe is open, the two pipes together can fill the pool in 4 hr. how long will it take the second pipe to fill the pool alone?

2. one pipe can fill a tank in 45 min and another pipe can fill it in 30 min. if these two pipes are opened and a third pipe is draining water from the tank, it takes 27 min ti fill the tank. how long will it take the third pipe alone to empty a full tank?

Answer 1

1) first pipe = 1/10 per hour

second pipe = x per hour

4 ( 1/10 + x) = 1 complete job

4/10 + 4x = 1

4x = 6/10

x= 1.5 / 10

In 20/3 hours, or 6 2/3 hours the second pipe can fill the pool

2) first pipe = 1/45 per min

second pipe = 1/30 per min

third pipe = -x per min

27/45 + 27/30 -x = 1

3/5 + 9/10 - x = 1

6/10 + 9/10 -x = 1

3/2 - x = 1

x = 1/2

Third pipe must drain half of pool in 27 minutes

The third pipe will drain pool in 54 minutes

Answer 2

1 pipe 1 fills at 10% an hour so in 4 hours it filt up 40% of the pool

so the other pipe did 60% in 4 hours so it fills at 15% an hour

so 100/15=6.6 by it self it would take 6.6 hours

to lazy to do the second one but try doing it with the same tecniq like how much they fill in 1minute eg the first pipe fills at 2.2% an min