Which of these is closest to the number of seconds in one day?
Hints
Take them one at a time. The first gives nothing away.
1A nudge
Go hours, then minutes, then seconds.
2The strategy
Convert one step at a time and check the size after each step. Because the choices are far apart, a rough calculation is enough to pick the right one.
3The full solution
24 hours is 24 x 60 = 1440 minutes, and 1440 x 60 = 86400 seconds.
Solution— no shortcut on this one
Convert in stages. A day is 24 hours, which is 24 x 60 = 1440 minutes, which is 1440 x 60 = 86 400 seconds. Even roughly: 1400 x 60 is about 84 000, which already separates the choices decisively. The transferable idea: when the choices are far apart, a rough calculation picks the answer and costs a fraction of the time.
Why this is on the test: Widely spaced choices are an invitation to estimate, and every wrong choice here is the answer to a different, easier question.