Percentage increase

[Mo2men]

If the price increased by X% from 2001 to 2002 and by Y% from 2002 to 2003, what is the percentage increase from 2001 to 2003?


(1) XY=30

(2) 100X+100Y+XY=800

[GMATGuruNY]

If the price increased by X% from 2001 to 2002 and by Y% from 2002 to 2003, what is the percentage increase from 2001 to 2003?


(1) XY=30

(2) 100X+100Y+XY=800

If a value increases by x% and then by y%, the total percent increase = x + y + xy/100.
I discuss this issue here:
https://www.beatthegmat.com/quick-way-to ... 82917.html

Question stem, rephrased:
What is the value of x + y + xy/100?

Statement 1:
If x=1 and y=30, then x + y + xy/100 = 1 + 30 + 30/100 = 31 + 3/10.
If x=2 and y=15, then x + y + xy/100 = 2 + 15 + 30/100 = 17 + 3/10.
Since x + y + xy/100 can be different values, INSUFFICIENT.

Statement 2:
100x + 100y + xy = 800.
If we divide both sides by 100, we get:
x + y + xy/100 = 8.
SUFFICIENT.

The correct answer is B.