Subtract 8-4 1/2. A. 3 B. 4 C. 4 1/2 D. 3 1/2
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Answer:
Step-by-step explanation:
From the problem we know that 12% of Lisa's original weight is 21 pounds. Let's call Lisa's original weight x and rewrite what we know from the question in terms of x.
We can convert 12% into a decimal - 0.12. We can also recognize that the word "of" used in a word problem often means you need to multiply. So, we can multiply 0.12 by x because we know 12% of Lisa's original weight.
0.12x = 21
To solve this equation, we need to isolate x, so we can divide both sides by 0.12.
x = 175. ==> Lisa's original weight was 175 pounds.
If you don't have a calculator or would like to learn another way to solve this problem, you can use proportions.
We know that 12% of x is 12, so what is 100% of x? (this is another way to rewrite the question)
We can contine to rewrite this by writing
We can write this because we know that the ration of 12% to 21 pounds is going to be the same ratio of 100% to Lisa's entire body weight.
We can multiple by both sides of the equation by , which is equal to 1 so it won't change the value of the equation, to remove the denominators. Then, we'll end up with:
12x = 100*21
12x = 2100
x = 175