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Pearson Algebra 1 Common Core, 2011

PA

Pearson Algebra 1 Common Core, 2011 View details

5. Samples and Surveys

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Exercise 43 Page 759

The percent proportion is a proportion that equates a part of a whole to a percent out of 100.

B

Practice makes perfect

The percent proportion is a proportion that equates a part of a whole to a percent out of 100. part/whole=percent/100 ⇔ a/b=p/100 We can find what percent 50 of an unknown number b is by thinking about 50 as a part and b as the whole. Let's substitute a= 50 and p= 40 into the formula and solve for b.

a/b=p/100

a= 50, p= 40

50/b=40/100

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Solve for b

a/b=.a /10./.b /10.

50/b = 4/10

Cross multiply

50* 10 = 4* b

Multiply

500 = 4b

Rearrange equation

4b = 500

.LHS /4.=.RHS /4.

b = 125

Therefore, 50 is 40 % of 125. This corresponds to answer B.

Subchapter links

Lesson Check p.756

Practice and Problem-Solving Exercises p.756-759

Standardized Test Prep p.759

Mixed Review p.759