Answer:
13 pencils.
Step-by-step explanation:
Let x be the pens and y be the pencils
Given:
Brian purchased pens for 75 cents each and pencils for 40 cents each he bought total of 22 writing utensils for $11.95.
Total pens and pencils is 22
So, [tex]x+y=22[/tex]----------------(1)
And he bought all utensils for $11.95. and each pen for 75 cents and pencils for 40 cents.
[tex]0.75x+0.40y=11.95[/tex]------------(2)
solve equation 1 and equation 2 for x and y.
From equation 1.
[tex]x+y=22[/tex]
[tex]y=22-x[/tex]----------------(3)
put y value in equation 2.
[tex]0.75x+0.4(22-x)=11.95[/tex]
[tex]0.75x+0.4\times 22-0.4x=11.95[/tex]
[tex]0.75x+8.8-0.4x=11.95[/tex]
[tex]0.75x-0.4x=11.95-8.8[/tex]
[tex]0.35x=3.15[/tex]
[tex]x=\frac{3.15}{0.35}[/tex]
[tex]x=9[/tex]
Now substitute x value in equation 3.
[tex]y=22-9[/tex]
[tex]y=13[/tex]
So, he buy 13 pencils.