CoffeeCreamSugar wrote:

Dara ran on a treadmill that had a readout indicating the time remaining in her exercise session. When the readout indicated 24 min 18 sec, she had completed 10% of her exercise session. The readout indicated which of the following when she had completed 40% of her exercise session?

A. 10 min 48 sec

B. 14 min 52 sec

C. 14 min 58 sec

D. 16 min 6 sec

E. 16 min 12 sec

Do a more efficient single calculation:

24 min 18 sec is 90% of her exercise time.

When she completes 40% of her exercise session, the readout will indicate 60% of the time.

So we need \(\frac{6}{9} * 24(\frac{18}{60}) = \frac{81}{5} = 16 ( \frac{1}{5}) = 16 (\frac{12}{60}) =\)16 min 12 sec

*Edited a calculation error.

Hi. Could you please explain the reasoning behind the last part? How did get to the 81/5?