Mathmetics

ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams

Q21.
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is:
1) 40 2) 80
3) 120 4) 200
5)None of these
Answer : 40
Explanation :
Let the numbers be 3x, 4x and 5x.
Then, their L.C.M. = 60x.
So, 60x = 2400      or x = 40.
The numbers are (3 x 40), (4 x 40) and (5 x 40).
Hence, required H.C.F. = 40.
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Q22.
The ratio of two numbers is 3 : 4 and their H.C.F. is 4. Their L.C.M. is:
1) 12 2) 16
3) 24 4) 48
5)None of these
Answer : 48
Explanation :
Let the numbers be 3x and 4x. Then, their H.C.F. = x. So, x = 4.
So, the numbers 12 and 16.
L.C.M. of 12 and 16 = 48.
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Q23.
Find the two natural numbers whose sum is 85 and the LCM is 102
         

1) 1) 30 and 55 2) 2) 17 and 68
3) 3) 35 and 55 4) 4) 51 and 34
5)5) None of these
Answer : 4) 51 and 34
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Q24.
The H.C.F. of two numbers is 11 and their L.C.M. is 693. If one of the numbers is 77, find the other.
                
1) 1) 909 2) 2) 119
3) 3) 66 4) 4) 99
5)5) None of these
Answer : 4) 99
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