Find two numbers, both smaller than 100, that have common multiple of 450 and highest common factor of 15

hello :

90 = 15×6

75 =  15× 5

highest common factor of 90 and is 15 because highest common factor of 5 and 6 is 1

90 = 3² ×2×5

75= 5^3

common multiple of 90 and 75 is : 3²×2×5²  = 450

90 and 75  both smaller than 100.

answer: the answer is d