Answer:
4 x 10^7 i.e. 40000000
Explanation:
(4x10^7) is obtained by multiplying (5x10^2) by (8x10^4).
The equation can be solved by multiplying the coefficients (5 and 8) first, adding the exponents (2 and 4), and writing the result in scientific notation:
(5 x 8) x 10^(2 + 4) = 40 x 10^6 = 4 x 10^7.
Hope it helps! : )