Problema Solution
An inlet pipe can fill a large water tank in 20
hours. Another inlet pipe can fill the same
water tank in 30 hours. Given an
empty water tank, at 8:00 AM, Monday, Sept. 21st., activate both pipes.
Question: What time on the clock will it be when
the tank is completely filled? Round to nearest minute on clock, noting AM or PM.
Answer provided by our tutors
The inlet pipe that can fill the tank in 20 hours has a rate of 1/20 tank per hour.
The other inlet pipe that can fill the tank in 30 hours has a rate of 1/30 tank per hour.
Let 'x' represent the time needed for the tank to fill both of the pipes are active.
1/x tank per hour is the together rate of the pipes.
Now we can write:
1/20 + 1/30 = 1/x
........
click here to see the equation solved for x
........
x = 12 hr
At 8:00 AM Monday, Sept. 21st., both pipes were activates.
After 12 hours the time is 8:00 PM Monday, Sept. 21st.
The tank will be completely filled at 8:00 PM Monday, Sept. 21st.