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# Class 7 Mathematics questions and answers on LCM, GCD and HCF

Class 7 Mathematics questions and answers on whole number operations: LCM, GCD and HCF

Lessons (**18**) * SHARE*

- 1.
What is the L.C.M of 15, 20 and 30?
A. 120
B. 60
C. 15
D. 5

4m 20s - 2.
In a school, one bell rings after every 30 minutes while the other rings after every 35 minutes. If the two bells rang together at 8.15 am, at what time did they ring together next?
A. 11.45 am
B. 3.30 am
C. 9.20 am
D. 1.45 am

6m 41s - 3.
Three clocks were set to ring at intervals as follows:
The first every 6 minutes
The second after every 15 minutes
The third after every 24 minutes
If the clocks were set at the same, after how many minutes did they ring together?
A. 30
B. 45
C. 120
D. 2160

5m 32s - 4.
Kamau wants to get change for a sh 1000 note. The change is to consist of sh 500, sh 200, sh 100 and sh 50 notes. What is the smallest number of notes he can get?
A. 4
B. 5
C. 6
D. 7

4m 19s - 5.
What is the difference in the value between the LCM of 8 and 1, and the GCD of 36 and 54?
A. 104
B. 84
C. 14
D. 6

7m 2s - 6.
What is the Greatest Common Divisor (GCD) of the numbers 32, 48 and 56?
A. 8
B. 168
C. 672
D. 86016

3m 54s - 7.
What is the smallest number that can be divided by 12, 18 and 27 without a remainder?
A. 108
B. 36
C. 3
D. 5832

4m 21s - 8.
By how much is the LCM of 40 and 60 more than their GCD?
A. 20
B. 100
C. 120
D. 140

7m 15s - 9.
What is the Greatest Common Divisor of 120 and 270?
A. 3
B. 10
C. 30
D. 1080

3m 53s - 10.
What is the difference between the LCM and the GCD of the numbers 24, 32 and 40?
A. 8
B. 472
C. 480
D. 488

8m 43s - 11.
Three bells are set to ring out at intervals of 4 minutes, 6 minutes and 9 minutes respectively. If they all ring together now, after how many minutes will they ring together next?
A. 12
B. 18
C. 36
D. 216

4m 22s - 12.
What is the LCM of 30, 45 and 60?
A. 15
B. 135
C. 180
D. 540

4m 36s - 13.
What is the difference between the LCM and the HCF of the numbers 18, 24 and 72?
A. 6
B. 66
C. 72
D. 78

7m 44s - 14.
What is the difference between LCM of 12 and 24 and the GCD of 54 and 36?
A. 42
B. 24
C. 18
D. 6

7m 0s - 15.
What is the product of LCM and HCF of numbers 10, 20 and 40?
A. 10
B. 40
C. 50
D. 400

7m 18s - 16.
In a race, Korir takes 12 seconds to run round the field. Muteti takes 18 seconds while Mwenda takes 27 seconds to run round the same field. If the three athletes start together, after how many seconds will they be together again?
A. 3
B. 57
C. 5832
D. 108

5m 50s - 17.
The following are prime factors of three numbers:
(i) #2^2times 3^2#
(ii)# 2^3times 5#
(iii) #2^4times 3^2#
What is the LCM of the three numbers?
A. 4
B. 30
C. 180
D. 720

8m 25s - 18.
Ngenya refuels his car after every two days, Kerubo refuels hers after every four days while Masai refuels his after every eight days. If they all refueled their cars on 3rd March 2013, on which date did they refuel their cars together?
A. #17^(th)# March
B. #11^(th)# March
C.# 7^(th)# March
D. #5^(th)# March

4m 16s