Question

The speed of the boat is 20 km in an hour. How long will it take to cover 85 km?
(4 marks)

Answer 1

Solution:
The boat travels at a speed of 20 km in one hour.
Distance covered by boat in 4 hours = 4 × 20 km
= 80 km (1 mark)
We know that,5 km = 20 ÷ 4 = $\frac{1}{4}of20km$ (0.5 marks)
Time taken to travel 5 km =$\frac{1}{4}of1hr$ (0.5 marks)
So, the boat can go the next 5 km in Quarter of an hour.
1 hour = 60 mins (0.5 marks)
Quarter hour $=\frac{1}{4}\times 60mins=15mins$ (0.5 marks)
Thus, the total time taken by the boat to cover 85 km = 4 hours 15 min (1 mark)