Two trains start 420 miles apart and travel toward each other, one at 70 miles per hour and the other at 60 miles per hour. How long until they meet?

Correct answer to question 178 (Arithmetic Reasoning): 3.23 hours

Method

When two objects close a gap toward each other, their speeds add. Together they close 70 + 60 = 130 miles every hour, so the 420 mile gap closes after 420 divided by 130, about 3.23 hours.