LCM and HCF
-  The LCM of four consecutive numbers is 60. The sum of the first two numbers is equal to the fourth number. What is the sum of four numbers?
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                        View Hint View Answer Discuss in Forum We find LCM of 60 ,  
 ∴ 60 = 2 × 2 × 3 × 5
 i.e., Numbers = 2, 3, 4 and 5Correct Option: BWe find LCM of 60 ,  
 ∴ 60 = 2 × 2 × 3 × 5
 i.e., Numbers = 2, 3, 4 and 5
 ∴ Required sum = 2 + 3 + 4 + 5 = 14
-  The LCM fo two prime numbers p and q, (p > q) is 161. The value of (3q – p) :
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                        View Hint View Answer Discuss in Forum LCM of p and q = 161 
 ∴ pq = 23 × 7
 ∴ p = 23; q = 7
 ∴ 3q – p = 3 × 7 – 23Correct Option: ALCM of p and q = 161 
 ∴ pq = 23 × 7
 ∴ p = 23; q = 7
 ∴ 3q – p = 3 × 7 – 23
 The value of (3q – p) = 21 – 23 = – 2
-  Three electronic devices make a beep after every 48 seconds, 72 seconds and 108 seconds respectively. They beeped together at 10 a.m. The time when they will next make a beep together at the earliest is
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                        View Hint View Answer Discuss in Forum Required time = LCM of 48, 72 and 108 seconds  
 ∴ LCM = 2 × 2 × 2 × 2 × 3 × 3 × 3 = 432 seconds = 7 minutes 12 secondCorrect Option: ARequired time = LCM of 48, 72 and 108 seconds  
 ∴ LCM = 2 × 2 × 2 × 2 × 3 × 3 × 3 = 432 seconds = 7 minutes 12 second
 ∴ Required time = 10 a.m. + 7 minutes 12 second = 10 : 07 : 12 hours
-  Three tankers contain 403 litres, 434 litres, 465 litres of diesel respectively. Then the maximum capacity of a container that can measure the diesel of the three containers exact number of times is
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                        View Hint View Answer Discuss in Forum Greatest capacity of measuring vessel 
 = HCF of 403 litres, 434 litres and 465 litres
 First of all we find HCF of 403 and 434 
 Again , HCF of 31 and 465 Correct Option: AGreatest capacity of measuring vessel 
 = HCF of 403 litres, 434 litres and 465 litres
 First of all we find HCF of 403 and 434 
 Again , HCF of 31 and 465 
 ∴ Greatest capacity of measuring vessel = 31 litres
-  The greatest number that will divide 729 and 901 leaving remainders 9 and 5 respectively, is
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                        View Hint View Answer Discuss in Forum We know that the largest number which when divide the numbers a, b and c give remainders as p, q, r respectively is given by H.C.F. of (a – p), (b – q) and (c – r). 
 Required number = HCF of (729 – 9) = 720 and (901 – 5) = 896 
 H.C.F = 16Correct Option: BWe know that the largest number which when divide the numbers a, b and c give remainders as p, q, r respectively is given by H.C.F. of (a – p), (b – q) and (c – r). 
 Required number = HCF of (729 – 9) = 720 and (901 – 5) = 896 
 H.C.F = 16
 Hence , required answer = 16.
 
	