Answer:
23.75%
Step-by-step explanation:
Use formula

where
I = interest,
P = principal,
r = rate (as decimal),
t = time (in years).
In your case,

Substitute:

Answer:
18
Step-by-step explanation:
What number is 90% of 20?
18
What is 90 percent (calculated percentage %) of number 20? Answer: 18.
1,900,000,000 in scientific notion is
1.9 ×10^9