Question

1. Two boats A and B depart from a port at the same time, travels to the north at 15 miles per hour, while B travels eastward at 20 mph. How fast boats are separated two hours after they left the port?

Answer 1

50 mi

Explanation:

Two hours after leaving port,

• Boat A has travelled 30 mi north
• Boat B has travelled 40 mi east.

The triangle formed by their tracks and the line joining their current positions is a right-angled triangle.

According to Pythagoras,

a² + b² = c²

30² + 40² = c²

900 + 1600 = c²

2500 = c²

√(2500) = c

c = 50 mi

The boats will be separated by 50 mi two hours after leaving port.