Question

A ship can cover a certain distance in 10 hours at a speed of 16 nautical miles per hour. By how much should its speed be increased so that it takes only 8 hours to cover the same distance? 

(A nautical mile in a unit of measurement used at sea distance or sea water i.e. 1852 metres).

Answer 1

Speed and distance are in inverse proportion.

⇒ x₁y₁ = x₂ y_{2 ,} Let x₂ = x (say)

⇒ 16 × 10 = x × 8

⇒ x = (16×10) / 8 = 20

∴ x = 20

∴ The speed to be increased

= 20 – 16 

= 4 nautical miles