Find the common factors of 15 and 18. Choices.
A) 50
B) 55
C) 60
D) 70
E) 90
First of all we need to find the prime factors of 15 and 18   15 = 5 x 3   18 = 3x 3 x 2   LCM is the product of highest exponent of all the factors.   LCM (15,18) = 5 x 3^2 x 2   = 90   ANSW90R : 90
<result>E</result>
Find the common factors of 15 and 18.