Short Answer: 9x + 13
Step by Step:
4x + 5x = 9x
3 + 10 = 13
Hope this helps!
Given:
The population of continent of South America in 2010 is 395, 280, 204.
To find:
The closest estimate of this number.
Solution:
We have,

The approximate value of this number is

The scientific form of this value is

Therefore, the correct option is C.
The standard form would be 602,547