Question

If 5/9 of a tank can be filled in 2 minutes, how many minutes will it take to fill the whole tank ? A) 2.4 minutes B) 2.8 minutes C) 3.2 minutes D) 3.6 minutes

Answer 1

d

Explanation:

Answer 2

D.

Explanation:

Set this up as a ratio with #parts of tank on top and #minutes on the bottom and then solve it as a proportion with x being the unknown number of minutes in the second ratio.

`((5)/(9) )/(2)=(1)/(x)`

Notice the 1 in the numerator of the second ratio. This is because a whole tank is represented by 9/9 which is the same thing as 1.

Cross multiply to solve for x:

`(5)/(9)x=2(1)`

To solve for x we will multiply both sides by 9/5:

`((9)/(5))((5)/(9))x=2((9)/(5))`

9/5 and 5/9 cancel each other out when multiplied leaving simply "x" on the left. And multiplying on the right:

`x=(18)/(5)`

which divides to 3.6 minutes