4. A fish tank can be filled in 10 minutes using both pumps A and B si

1.	4. A fish tank can be filled in 10 minutes using both pumps A and B simultaneously. However,pump B can pump water in or out at the same rate. If pump B is inadvertently run in reverse,then the tank will be filled in 30 minutes. How long would it take each pump to fill the tank byitself ? (Use Cramer's rule to solve the problem).
Answer» Let Say A alone take = A mins Then tank filled by A in 1 min = 1/A Tank filled by A & B together in 1 min = 1/10 tank filled by B alone in 1 Min = 1/10 - 1/A = (A-10)/10A if B id reversed then both takes 30 min means tank filled in 1 min = 1/10 1/A - (A-10)/10A = 1/30 multiplying by 30A both sides => 30 - (3A-30) = A => 60 = 4A => A = 15

4. A fish tank can be filled in 10 minutes using both pumps A and B simultaneously. However,pump B can pump water in or out at the same rate. If pump B is inadvertently run in reverse,then the tank will be filled in 30 minutes. How long would it take each pump to fill the tank byitself ? (Use Cramer's rule to solve the problem).

Answer»

Let Say A alone take = A mins

Then tank filled by A in 1 min = 1/A

Tank filled by A & B together in 1 min = 1/10

tank filled by B alone in 1 Min = 1/10 - 1/A = (A-10)/10A

if B id reversed then both takes 30 min

means tank filled in 1 min = 1/10

1/A - (A-10)/10A = 1/30

multiplying by 30A both sides

=> 30 - (3A-30) = A

=> 60 = 4A

=> A = 15