Prime Factors, HCF & LCM (CIE IGCSE Maths: Core)

Find the lowest common multiple (LCM) of 48 and 60.

Write 195 as a product of its prime factors.

Find the lowest common multiple (LCM) of 15 and 27.

Write 432 as the product of its prime factors.

Find the highest common factor (HCF) of 24 and 108.

Find the highest common factor (HCF) of 90 and 48.

Write 56 as a product of its prime factors.

Find the lowest common multiple (LCM) of 56 and 42.

Find the lowest common multiple (LCM) of 28 and 35.

Find the lowest common multiple (LCM) of 12 and 78.

Find the highest common factor (HCF) of 12 and 78.

Write 18 as the product of its prime factors.

At a bus stop

• a red bus arrives every 18 minutes

and

• a blue bus arrives every 24 minutes.

At 1047 a red bus and a blue bus arrive.

Find the next time when a red bus and a blue bus arrive together.

Find the highest common factor (HCF) of 126 and 180.

Gerry and Alain run around a running track.

To run around the track once

• Gerry always takes 90 seconds
• Alain always takes 105 seconds.

They start together at the same point.

After how many minutes are they next together at that point?

........................................ min 

Talan completes one lap of a racetrack every 80 seconds.

[2]

A northbound train leaves Lexford Station every 30 minutes.
A bus leaves Lexford Station every 45 minutes.

At 11 40 a northbound train and a bus leave the station together.

Find the next time when this happens.

[2]

Find the value of .

= .......................  [1]