Answer:
A
Step-by-step explanation:
Equation
300 ( 1 + x) = 420
Explanation
You start with 300. What fractional amount do you need to increase the original amount up to 420
Solution
Divide both sides by 300
300(1 + x)/300 = 420/300
1 + x = 1.4
Subtract 1 from both sides.
1 - 1 + x = 1.4 - 1
x = 0.4
But as a percent this number is 0.4 * 100 = 40%
Answer
40% which is A
