I=prt
I interest earned
P principle 4000
R interest rate 0.095
T time270/365
I=4,000×0.095×(270÷365)
I=281.10
0.10x - 0.08x = 250 - 185
0.02x = 65
x = 3250
Here's one shortcut:
2.3×10^9=1000(2.3×10^6) because your adding 3 more zeros to 2300000
Option C: 
Option D: 
Option F: 
Solution:
Given expression: 
To find which expression is equivalent to the given expression.
Let us solve this using exponent rule: 
Option A: 

It is not equivalent expression.
Option B: 

It is not equivalent expression.
Option C: 

It is equivalent expression for the given expression.
Option D: 

It is equivalent expression for the given expression.
Option E: 

It is not equivalent expression.
Option F: 

It is equivalent expression for the given expression.
Hence
are the equivalent expressions.
Option C, Option D and Option F are correct answers.