Interview Q&A / Aptitude

1. If a boy walks to school at 5 km/h he is 7 minutes late; at 6 km/h he is 5 minutes early. How far is the school?

   6 km. The two journey times differ by 7 + 5 = 12 minutes = 1/5 hour. So d/5 - d/6 = 1/5, which gives d/30 = 1/5 and d = 6 km.

   IntermediateQuick answer1 min read
2. In a 1 km race, A beats B by 100 m and B beats C by 100 m. By how many metres does A beat C?

   190 m. When A runs 1,000 m, B runs 900 m. When B runs 1,000 m, C runs 900 m, so when B runs 900 m, C runs 810 m. Hence A beats C by 1,000 - 810 = 190 m.

   IntermediateQuick answer1 min read