Question

two pipes X and Y can seperately fill a tank in 10 minutes and 15 minutes resp. both the pipes are opened together and 4 minutes later tap connecting pipe X is turned off. how much more will it take to fill the tank

Answer 1

Answer:

9 min

Step-by-step explanation:

let time taken to completely fill the tank be a.

in 10 min 1 part tank is filled by x.

in 1 minute1/10 part tank is filled.

since after 4 minutes pipe connected to tank x is turned off.

so in 4 minutes tankis filled=4/10 part

in 15 minutes one part of tank y is filled.

in 1 minutes 1/15 part of tank y is filled.

in x minutes a/15 part of tank y is filled.

so the equation becomes

x and y fill total one part is filled.

4/10+x/15=1

x/15=6/10

x=6/10×15

x=9min

Answer 2

Answer:

5 min correct answer 20x+2x=30

2x=10

x=5