Answer:
12.5%
Step-by-step explanation:
The price increased from 800 to 900. So what is the PERCENTAGE INCREASE??
The increase is 900 - 800 = 100
To find this in terms of original, we need to divide 100 by 800 and multiply by 100 to get the "percentage". Let's do it:

So the increase is 12.5% and thus the general sales tax is 12.5%
Numbers with more than two divisors are called composite numbers. The first 20 primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, and 71.