SOLUTION: 2.8 x 10 to the 23rd(power) is what percent of 5.6 x 10 to the 24th(power)? this is my daughters first day of algebra. Last year her National test scores came back high so they p

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Question 8040: 2.8 x 10 to the 23rd(power) is what percent of 5.6 x 10 to the 24th(power)?
this is my daughters first day of algebra. Last year her National test scores came back high so they put her is the class. She never had pre-algebra and she doesn't have a text book yet. What is the formula? Please help....
Answer by bonster(299) About Me  (Show Source):
You can put this solution on YOUR website!
%282.8%29%2810%5E23%29
%285.6%29%2810%5E24%29

first of all, don't be scared off by the large exponenent!
The question asked what percent 2.8 *10%5E23 is of 5.6*10%5E24 so we must put it in division form.

%282.8%29%2810%5E23%29+%2F+%285.6%29%2810%5E24%29

before I go any further, let's work on a problem that's a little easier...
what if the problem read:
%282.8%29%2810%5E3%29+%2F+%285.6%29%2810%5E4%29
you'd write it as: %282.8%29%2810%29%2810%29%2810%29+%2F+%285.6%29%2810%29%2810%29%2810%29%2810%29
do you see how 3 10's would cancel out?
You'd be left with: %282.8%29+%2F+%285.6%29%2810%29 or %282.8%29+%2F+%285.6%29%2810%5E1%29


NOW, going back to our problem:
%282.8%29%2810%5E23%29+%2F+%285.6%29%2810%5E24%29, I know that 23 of the 10's would be canceled out. So we would be left with: %282.8%29+%2F+%285.6%29%2810%5E1%29

%282.8%29+%2F+%285.6%29%2810%29=%282.8%29+%2F+%2856%29
%280.4%29%287%29+%2F+%288%29%287%29
The seven's cancel out
%280.4%29+%2F+%288%29
another way of getting 0.4=%280.1%29%284%29
%280.1%29%284%29+%2F+%284%29%282%29
The 4's cancel out
.1%2F2
which is .05
in order to get the percentage, multiply .05 by 100
(.05)(100)
=5%
***You should get her a pre-algebra book and go through it really quickly with her!***