Answer:
The % increase is 7.179 but see the remark I made below. What I have given and what it could be is a rounding error. Less than 2 dollars error is not much when you are calculating something for someone just to show them how to do it.
Step-by-step explanation:
242,555 * x/100 = 259,970 Multiply by 100
242,555 * x = 259970 * 100
242,555 * x = 25997000 Divide by 242555
x = 24997000/242444
x = 107.179
That's the total increase.
What you want is 7.179%
If you take 7.179% of 242,555 and add it onto 242555 you should get 259,970
7.1797/100 * 242555 = 17413.02
17413.02 + 242555 = 259968.02
Why isn't it exact. I'm out just about 2 whole dollars. The reason is that the % isn't exact. It's only out to 3 decimal places which apparently is not enough. You can go over my numbers if you want more exactness us use something that is rounded to 7.180 if you like.
