Step-by-step explanation:
first, let's bring them to the same exponent of 10.
8.5 × 10⁸ is already scientific notation
42 × 10⁷ = 4.2 × 10⁸ (this is now scientific notation AND it is using the same exponent of 10)
so, how many times is the first one greater ?
(8.5 × 10⁸) / (4.2 × 10⁸) = 8.5 / 4.2 = 2.023809524...
so, the first number is 2.023809524... times greater than the second number.
maybe you made a typo ?
maybe the second number was actually 42.5 × 10⁷ ?
because then
42.5 × 10⁷ = 4.25 × 10⁸
and
8.5 / 4.25 = 2
so,
8.5 × 10⁸ is 2 times greater than 42.5 × 10⁷ or 4.25 × 10⁸.