Last year's sales = $320 million;
This year's sales = $385 million;
Increase = $65 million.

Now, 20% of $320 million is $64 million, which is very close to actual increase of $65 million.

Answer: C.

OR:
General formula for percent increase or decrease, or percent change:

\(Percent=\frac{Change}{Original}*100\) --> \(Percent=\frac{65}{320}*100=\frac{13}{64}*100\approx{\frac{13}{65}}*100=20%\).

Answer: C.
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This might sound stupid, but how do we know that we need to round up 64 to 65 without losing to much time. I did this question before and it took over 2 min before i knew that i had to round 64 to 65 in order to solve the problem. Do you have any trick in mind?

65 is the closest multiple of 13: 5*13=65.
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last year= 320
this year = 385

((385-320)/320)*100 = (65/320 )*100 approx.. 20

Increase = 385 - 320 = 65

% Increase \(= \frac{65}{320} * 100 = 20%\)

Answer = C

Percentage increase = \(\frac{(Final - Original)}{Original}*100\)

Substituting the values here

\(\frac{(385 - 320)}{320}\)* 100 = (65/320)*100 = 20% approx
Option C

The problem is testing us on using the percent change formula:

(New Value – Old Value)/Old Value x 100

We are given:

February sales this year = 385 million

February sales last year = 320 million

We need to determine the percent increase between sales from last year to sales this year.

Thus, the new value = 385 million and the old value = 320 million. Let’s plug them into our percent change formula.

(New Value – Old Value)/Old Value x 100

[(385 – 320)/320] x 100

65/320 x 100

13/64 x 100 ≈ 13/65 x 100 ≈ 1/5 x 100 ≈ 20%.

The answer is C.
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First thing is you can approximate since the percentages are wide apart.

385 - 320 = 65

original amount = 320 so every 32 is 10%

20% is equal to 64 M

so answer is slightly above 20% hence C is the closest answer.

Percentage increase = \(\frac{(Final - Original)}{Original}*100\)

\(\frac{(385 - 320)}{320}*100\)

\(\frac{(65)}{320}*100\)

\(\frac{(65)}{32}*10\) Cross off a zero from 320 and 100

\(\frac{65}{32}\) is close to 2, so 2 * 10 = 20%

Answer is C

\(\frac{65}{320}*100\) ~ \(20\)%

Thus, Answer must be (C)
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\(\frac{new - old }{ old}\)

\(\frac{385 - 320 }{ 320}\)

\(\frac{65 }{ 320}\) = approximately 20%

Answer is C.
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