The product of the smallest common multiple and the biggest common factor of 30, 36 and 42 is:

Correct option is A

Let's find the prime factorization of each number:
30 = 2 x 3 x 5
36 = 2 x 2 x 3 x 3
42 = 2 x 3 x 7
The smallest common multiple (LCM) is the product of the highest powers of each prime factor that appears in the numbers:
LCM = 22 x 32 x 5 x7 = 1260
The greatest common factor (GCF) is the product of the common prime factors raised to the lowest powers:
GCF = 2 x 3 = 6
The product of LCM and GCF is:
1260 x 6 = 7560
Therefore, the product of the smallest common multiple and the biggest common factor of 30, 36 and 42 is 7560.
So, the correct answer is (a) 7560