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The HCF and LCM of two numbers are 66 and 384 respectively. If the first number is divided by 2, the resulting answer is 66. The second number is? 
A) 192
B) 196
C) 384
D) 576
Correct Answer : 192 Explanation : First number= 66 * 2 = 132 
The LCM of two numbers is 280 and the ratio of the numbers of 7 : 8. Find the numbers? 
A) 70 and 48
B) 42 and 48
C) 35 and 40
D) 28 and 32
Correct Answer : 35 and 40 Explanation : Let the two numbers are 7x and 8x and LCM is 56x. 
HCF of 105, 150 and 210 is x, HCF of 126, 396,1080 is y and HCF of 440, 180 and 280 is z. Which of the following is greatest? 
A) x
B) y
C) z
D) All are equal
Correct Answer : z Explanation : HCF of 105, 150, 210 
The five bells start ringing together and they toll at intervals of 6, 7, 8, 9 and 12 seconds respectively. After how many seconds will they toll together again? 
A) 72
B) 612
C) 504
D) 318
Correct Answer : 504 Explanation : Least common multiples (LCM) of ( 6, 7, 8, 9 and 12) = 504 
A, B and C starts running in the same direction from the same point and the same time in a circular stadium . A completes one round in 252 seconds, B in 308 seconds, and C in 198 seconds. When will they meet again at the starting point? 
A) 28 minutes 18 seconds
B) 42 minutes 36 seconds
C) 45 minutes
D) 46 minutes 12 seconds
Correct Answer : 46 minutes 12 seconds Explanation : Least common multiples (LCM) of (252 ,308 and 198) = 2772 sec 
The LCM of two numbers is 520 and HCF is 4. If a number is 52,what will be the second number? 
A) 40
B) 42
C) 50
D) 52
Correct Answer : 40 Explanation : 1st number ×2nd number = LCM × HCF 52 * 2nd number = 520 * 4

The HCF and LCM of two natural numbers are 12 and 72 respectively. What is the difference between the two numbers, if one of the numbers is 24? 
A) 12 B) 18 C) 21 D) 24 Correct Answer : 12 Explanation : As we know that, First number * Second number = LCM * HCF Difference between the two numbers = 36 − 24 = 12 
The two numbers are 63 and 77, HCF is 7, Find the LCM? 
A) 668 B) 693 C) 674 D) 680 Correct Answer : 693 Explanation : LCM = 63 * 77 / 7 = 693 
A natural number, when divided by 3, 4, 5, 6, and 7 respectively, leaves corresponding remainder of 2, 3, 4, 5 and 6. What is the smallest of all such numbers fulfilling the above condition ? 
A) 2519
B) 419
C) 209
D) 839
Correct Answer : 419 Explanation : Here 3 – 2 = 1, 4 – 3 = 1, 5 – 4 = 1, 6 – 5 = 1, 7 – 6 = 1 23, 4, 5, 6, 7 = (2*3*2*5*7) – 1 
HCF and LCM of two numbers are 82 and 574 respectively. if one of the numbers is 287, find the second number? 
A) 82
B) 164
C) 246
D) 41
Correct Answer : 164 Explanation : H.C.F. × L.C.M. = First number × Second number 82 * 574 = 287 * Second number 
Find the smallest square number which is exactly divisible by 3, 5, 15, 18, 20 and 24? 
A) 400
B) 900
C) 1600
D) 3600
Correct Answer : 3600 Explanation : Factorize the numbers as 3 = 3 LCM = 2*2*2*3*5 = 120 Now for it to be a perfect square, it should have even powers. it’s need to 2*3*5 to make perfect square So the least perfect square divisible by all these given terms is 3600 