poppe50 wrote:
I disregarded the minutes and only focused on the seconds since all answer options have a different seconds count.
18 seconds is 90% --> 20 seconds is 100% --> 60% is 12 seconds --> answer E
18 seconds is 90% --> 20 seconds is 100% --> 60% is 12 seconds --> answer E
This approach is incorrect, it gives the correct answer out of luck only because the 60% of the total minutes is an integer.
If you want you can separate them, but should be like this:
(1) 24 mins in 90%. Means that in 60%: 60*24/90 = 16 mins (simplify to calculate that)
(2) 18 secs in 90%. Means that in 60%: 60*18/90 = 12 secs (also simplifying)
if (1) turned out to be a fraction, then the answer would not just rely on the 12 secs you calculated.