AE wrote:

amorphous wrote:

From the per capita graph in 1981 the amount is approximately 380 and in 1982 the amount was approximately 420.

% increase = \(\frac{420-380}{420} * 100\) = 9.5% which is approximately 10%

we should divide by 420 or 380.

We divide by 420, the original number.

If you think about it, 420 - 380 = 40, and that's the actual increase that occured.

So we're left with \(\frac{40}{420}\), which tells us what fraction of the original number, 420, the increase, 40, is. So \(\frac{40}{420}\) is approximately equal to \(\frac{9.5}{100}\), or 9.5%. So, the increase of 40 is equal to an increase of 9.5% of our original number.