Question

The H.C.F. and L.C.M. of two numbers are 7 and 140 respectively. If the numbers are between 20 and 45, the sum of the numbers is _____.

• A. 70
• B. 77
• C. 63
• D. 56
• E. 29

Answer 1

The correct option is C 63

Since the H.C.F. is 7, therefore possible numbers could be 21, 28, 35 and 42. L.C.M. of the numbers does not have the factor of 3. But 21 and 42 are the numbers which have 3 as a factor. So, 21 and 42 will not be the numbers. If 21 and 42 are not the numbers, then the numbers are 28 and 35.
$\therefore$ Sum of the numbers $=28+35=63$