An old man driving bike at 80 km per hour. However being sugar patient, old man could not travel continuously. He takes small breaks each of 2 minutes for every 15 minute of his drive. How much distance the old man will cover in 90 minutes?

Explanation:-

For every 15 minutes he takes a rest of 2 minutes.
Hence,
for 90 minutes of drive he would require 12 minutes of rest.
Thus, he will be traveling for 90 - 12 = 78 minutes.
In 60 minutes he covers 80 Km.
In 1 minute he would cover ⁸⁰/₆₀ Km.
In 78 minutes he would cover (⁸⁰/₆₀) * 78 = 104 Km.