What is 6.25e15 x 2.40e8?

Answer 1

When multiplying, you add the exponents.

So we have 6.25 x 2.40 = 15.0 (3 significant figures)

We add the exponents: 15 + 8 = 23

This gives us 15.0x10²³

We then adjust the decimal and exponent to conform to scientific notation and end up with 1.50x10²⁴