Question

A number has 2,5 and 7 as its prime factors. what are the four smallest values it and take​

Answer 1

70, 140, 280, 350

Explanation:

Obviously, it must have the factors 2, 5, 7 as a minimum, so the smallest value is 2×5×7 = 70.

Any of these primes can be added to the product. In increasing order, the smallest additional factors will be 2, 4, 5, 7, 8, 10, ...

So, the four smallest numbers with prime factors of 2, 5, and 7 are ...

70 = 2·5·7

140 = 2²·5·7

280 = 2³·5·7

350 = 2·5²·7