If a tank of water is being drained at a rate of 39.0 cm3/sec, what is the rate in liters/min ?

Question

10-3 m3 = 1 L

Answer 1

there's a simple trick to answering this and all unit conversion questions. it's like this...

if you multiply 2 fractions, you can cancel out like terms. for example

1/2 x 2/3 = 1/3. you cancel the 2's since they are on the top and bottom of the / sign. you cancel them because 2/2 = 1 and 1 x any other number = that number. another example

1/3 x 6/5 = (1 x 6) / (3 x 5) = (1 x 2 x 3) / (3 x 5) = (1x2)/5 x 3/3 = 2/5 x 1 = 2/5

right?

consider unit conversions the same way. if you get cm on the top and on the bottom, they cancel. cm/cm = 1

likewise if 2.54 cm = 1 inch , then 1 = 1 inch / 2.54 cm so I can
multiply say 10 cm x 1 = 10 cm x 1 inch/2.54 cm = 3.94 inches
because the cm's cancel. ok?

so ,,

39 cm^3/sec x (1ml/cm^3) x (1 liter/1000 ml) x (60 sec/min) =
(39 x 1 x 1 x 60)/(1 x 1 x 1000 x 1) liters/min = ???

you do the rest

Answer 2

39 cm³/sec =

39 cm³/sec x ([60 sec/min] / [1000 cm³/L]) =

2.34 L/min

That's it!