Unit 3

4 marks · Easy

2. A cyclist travels for 20 minutes at a speed of 12 km/h and then for 40 minutes at a speed of 18 km/h.

(a)

Write the time taken for each part of the journey in hours.

[1 mark]

(b)

Calculate the total distance travelled.

[2 marks]

(c)

What is the cyclist's average speed for the whole journey?

[1 mark]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

(a) 20 minutes = 1/3 hour, 40 minutes = 2/3 hour

(b) 4 km (first part), 12 km (second part); total: 16 km

Show mark scheme and worked solution

Marking points

M1 (a) · 1 mark · Correctly converts minutes to hours for both parts

M2 (b) · 1 mark · Distance = speed × time for one part

A1 (b) · 1 mark · Correct total distance: 16 km

A2 (c) · 1 mark · Average speed correct to 16 km/h (follow-through)

Worked solution

a) 20 minutes = 20/60 = 1/3 h, 40 minutes = 40/60 = 2/3 h.

b) Distance 1 = 12 × 1/3 = 4 km; Distance 2 = 18 × 2/3 = 12 km; Total = 4 + 12 = 16 km.

c) Total journey time = 1 hour. Average speed = 16 km / 1 h = 16 km/h.