0

Quantitative Reasoning – Practice – A quick LCM and GCF question!

PSA_PRACTICE_QNR44. The LCM of two integers a and b is 4,200 and their GCF is 100.If neither a nor b is multiple of the other,find a+b.

Ans: Since, the GCF = 100, let the numbers be 100x and 100y such that x and y do not have any common factors (other than 1).

a + b = 100 (x + y)

LCM = 4200
=> 100 * x * y = 4200
=> xy = 42

(x,y) that satisfy the above equation= (1,42) , (2,21) ,(3,14) , (6,7)

(1,42) set is being rejected based upon the condition “neither a nor b is multiple of the other”.

However, in the rest three case all seem to be satisfying the condition.

Possible sum= 100 (2+21) , 100 (3+14), 100 (6+7)
=2300, 1700, 1300.

Leave a Reply

Your email address will not be published. Required fields are marked *