A small company has one color printer and one black-and-white printer, each printing at different rates. The color printer, working for 5 minutes and the black-and-white printer working, working for 3 minutes, print a total of 70 pages. When the black-and-white printer works for 6 minutes and the color printer works for 9 minutes, they print a total of 135 pages. This is modeled by the situation below, where b is the number of pages per minute of the black-and-white printer and c is the number of pages per minute of the color printer 3b + 5c = 70 and 6b + 9c = 135 How many pages per minute does the black-and white printer print?

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Answer:

The black-and white printer print can print 15 pages per minute.

Step-by-step explanation:

The given modeled equations are

3b + 5c = 70...(i)

6b + 9c = 135...(ii)

where b is the number of pages per minute of the black-and-white printer and c is the number of pages per minute of the color printer.

From equation (i), we have

[tex]3b=70-5c \\\\\Rightarrow b = \frac {70-5c}{3} \cdots(iii)[/tex]

Now, substitute the value of b in equation (ii), we have

[tex]6\times \frac {70-5c}{3}+9c=135 \\\\\Rightarrow 2(70-5c)+9c=135 \\\\\Rightarrow 140 - 10c+9c=135 \\\\\Rightarrow -c=135-140=-5 \\\\\Rightarrow c=5x^{2}[/tex]

By using equation (iii), we have

[tex]b = \frac {70-5\times5}{3}=\frac{45}{3}=15[/tex]

Hence, the black-and white printer print can print 15 pages per minute.

The black-and-white printer can print 15 pages per minute.

Given equations:

[tex]3b+5c=70[/tex]    ........(i)

[tex]6b+9c=135[/tex]  ........(ii)

Where b is the number of pages per minute of the black-and-white printer and c is the number of pages per minute of the color printer.

Solve the system of equations by substitution method

From (ii)

[tex]6b=135-9c\\b=\frac{135-9c}{6}[/tex]     ........(iii)

Put the value of b in (i), we get

[tex]3(\frac{135-9c}{6} )+5c=70\\\frac{135-9c}{2} +5c=70\\135-9c+10c=140\\c=5[/tex]

put c = 5 in (iii)

[tex]b=\frac{135-9(5)}{6} =\frac{90}{6} =15[/tex]

Therefore, The black-and-white printer can print 15 pages per minute.

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