Finding Common Ground Class 7 MCQ
hardFinding Common Ground Class 7 MCQ
Finding Common Ground Class 7 MCQ
Question 1.
The factors of a number 667 are two consecutive prime numbers p and q such that p > q. What is/are the factor(s) of the number (p - g)?
(a) 2 and 3
(b) 2 and 13
(c) 7
(d) 52
Solution:
(a) 2 and 3
Question 2.
If p is the greatest number which divides both 144 and 96, which of these is the greatest common factor of p - 3 and p + 2 ?
(a) 48
(b) 5
(c) 450
(d) 2880
Solution:
(b) 5
Question 3.
Which option lists the common factors of 212 and 112 and determines the greatest number that divides both of them?
(a) 212 × 112
(b) 2
(c) 2 × 2
(d) 4 × 28 × 53
Solution:
(c) 2 × 2
Question 4.
Which is smallest number divisible by both 48 and 76?
(a) 912
(b) 4
(c) 28
(d) 264
Solution:
(a) 912
Question 5.
Consider the conditions about the numbers m and n :
Condition 1 : both are 2-digits numbers
Condition 2 : one is odd and one is even
If m × n = 180, what is the smallest common multiple of m and n: ?
(a) 60
(b) 90
(c) 180
(d) 36
Solution:
(a) 60
Question 6.
Jagat has a jar of different coloured marbles. He is using them to make packs of marbles such that each pack has 12 red, 15 blue and 9 green marbles. After making packs, there are no marbles left in the jar.
What is the least possible number of marbles that could be in the jar at the beginning?
(a) 12
(b) 180
(c) 360
(d) 3
Solution:
(b) 180
Case Study
Question 1.
Number Cards
(a) A student draws two number cards from a bag containing number cards from 1 to 100. One of the numbers drawn is 8 more than the least two digit number and the other is three times the least two digit number. Two common factors of these numbers are:
(i) 9 and 6
(ii) 6 and 2
(iii) 6 and 5
(iv) 3 and 9
(b) What is the HCF of these two numbers ?
(c) What is the prime factorisation of the first number ?
(d) What is the LCM of these two numbers ?
(e) Which multiple of the HCF is the LCM of these numbers ?
Solution:
(a) (ii), because the numbers are 18 and 30
(b) 6
(c) 18 = 2 × 3 × 3
(d) 90
(e) 15th multiple
Question 2.
Ringing Bells
(a) It was observed that four different bells ring at intervals of 6 seconds, 8 seconds, 12 seconds and 18 seconds respectively.
What is the HCF of 6, 8, 12 and 18 ?
(b) What is the HCF of 6, 12 and 18 ?
(c) What is the LCM of 6, 8 and 12 ?
(d) What is the LCM of 6,8,12 and 18 ?
(e) If the above four bells ring together at 8 a.m., then at what time will they ring together again ?
(i) 8:01:24 a.m.
(ii) 8 : 00 : 48 a.m.
(iii) 8 : 01: 12 a.m.
(iv) 8 : 02 : 06 a.m.
Solution:
(a) 2
(b) 6
(c) 24
(d) 72
(e) (iii)