Problem 3 Solving a Multi-Step Proportion

What is the solution of the proportion b − 8 5 = b + 3 4 ? fraction b minus 8 , over 5 end fraction . equals . fraction b plus 3 , over 4 end fraction . question mark

b − 8 5 = b + 3 4   4 ( b − 8 ) = 5 ( b + 3 ) Cross Products Property 4 b − 32 = 5 b + 15 Distributive Property 4 b − 32 − 4 b = 5 b + 15 − 4 b Subtract  4 b  from each side . − 32 = b + 15 Simplify . − 47 = b Subtract  15  from each side and simplify . table with 6 rows and 3 columns , row1 column 1 , fraction b minus 8 , over 5 end fraction , column 2 equals . fraction b plus 3 , over 4 end fraction , column 3 , row2 column 1 , 4 . open , b minus 8 , close , column 2 equals 5 . open , b plus 3 , close , column 3 cap crosscap productscap property , row3 column 1 , 4 b minus 32 , column 2 equals 5 b plus 15 , column 3 cap distributivecap property , row4 column 1 , 4 b minus 32 minus 4 b , column 2 equals 5 b plus 15 minus 4 b , column 3 cap subtract . 4 b . fromeachside . . , row5 column 1 , negative 32 , column 2 equals b plus 15 , column 3 cap simplify , . , row6 column 1 , negative 47 , column 2 equals b , column 3 cap subtract . 15 . fromeachsideandsimplify . . , end table

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3. What is the solution of the proportion n 5 = 2 n + 4 6 ? n over 5 , equals . fraction 2 n plus 4 , over 6 end fraction . question mark

Problem 4 Using a Proportion to Solve a Problem

Music A portable media player has 2 gigabytes of storage and can hold about 500 songs. A similar but larger media player has 80 gigabytes of storage. About how many songs can the larger media player hold?

2  gigabytes 500  songs = 80  gigabytes s  songs Write a proportion . 2 s = 500 ( 80 ) Cross Products Property 2 s = 40 , 000 Multiply . s = 20 , 000 Divide each side by  2  and simplify . table with 4 rows and 3 columns , row1 column 1 , fraction 2 . gigabytes , over 500 , songs end fraction , column 2 equals . fraction 80 . gigabytes , over s , songs end fraction , column 3 cap writeaproportion . . , row2 column 1 , 2 s , column 2 equals 500 . open 80 close , column 3 cap crosscap productscap property , row3 column 1 , 2 s , column 2 equals 40 comma 000 , column 3 cap multiply , . , row4 column 1 , s , column 2 equals 20 comma 000 , column 3 cap divideeachsideby . 2 . andsimplify . . , end table

The larger media player can hold 20,000 songs.

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4. An 8-oz can of orange juice contains about 97 mg of vitamin C. About how many milligrams of vitamin C are there in a 12-oz can of orange juice?