How many minutes before 5pm is it if 30 mins ago it was four times as many minutes after 3pm?

The answer is 18 minutes. It made sense to me to sketch a timeline showing the 3 components of time given in the problem that add up to the 120 minute total span. (X = minutes before 5pm, 30 min gap, and 4X is time between 3pm and the start of the 30 min gap.) Visually and chronologically it would look something like: 3pm --> 4X --> 30 min --> X --> 5pm. So then algebraically, the equation is 4X + 30 min + X = 120 min. Therefore 5X = 90 or X = 18.

18 mins before 5 = 4:42. 30 before 4:42 puts the time at 4:12. There are 72 minutes between 3 and 4:42 divided by 4 is 18. So the answer is 18 mins before 5pm.

That last explanation seems like you need to know the answer before you even start trying to solve. My solution is as follows: 30 minutes before 5 is 4:30 leaving 90 minutes between 3 and then. The remaining time needs to be split into an interval so that x4 exists. The most logical interval would be in 5ths because the 4 proceeding intervals would be 4x greater then the following. 90/5=18 for each interval. 18 being four times less then 72 minutes proceeding it. This literally look me about a minute and a half to reason through, which I'm assuming the interviewer would not want to sit through. Guess I would fail.

You're forgetting the part where it says: "30 mins ago." It's not four times as many minutes since 3.

18

18

66

18

120 - x - 30 = 4 * x

Could someone show their math on this please - I had trouble on this question.