cleetus
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?
A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs
Check this:
word-translations-rates-work-104208.html?hilit=time%20work#p812628Let a, b and c be the time needed for A, B and C respectively to fill the tank alone.
Given:
\(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\) - combined rate of B and C is 7/6 of rate of A;
\(\frac{10}{3}*\frac{1}{c}=\frac{1}{a}+\frac{1}{b}\) - combined rate of A and B is 10/3 of rate of C;
\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{13}{60}\) - combined rate of A, B and C is 13/60 tank/hour;
Solving:
\(\frac{1}{a}+\frac{7}{6a}=\frac{13}{60}\) --> \(a=10\);
\(\frac{1}{c}+\frac{10}{3c}=\frac{13}{60}\) --> \(c=20\);
\(\frac{1}{10}+\frac{1}{b}+\frac{1}{20}=\frac{13}{60}\) --> \(b=15\).
Answer: B.