Respuesta :
Let's call the number of blue and black pens, respectively, [tex] b [/tex] and [tex] k [/tex]. We know that there are 29 pens in total, and no other colors. This means that
[tex] b+k = 29 [/tex]
i.e. the number of blue and black pens, together, must add up to 29.
Now, we also know that there are 3 more blue than black, which in other words means that the number of blue exceeds the number of black by 3:
[tex] b = k+3 [/tex]
We can use this expression to substitute [tex] b[/tex] in the first equation:
[tex] b + k = (k+3) + k = 2k+3 = 29 \iff 2k = 26 iff k = 13 [/tex]
So, there are 13 black pens. Since the blue are three more than the black, Suzie has 16 blue pens.
Hello!
Let's put this a system of equations, with y being the blue pens and x being the black.
y=x+3
x+y=29
Let's plug in our value for y into the second equation and solve for x.
x+x+3=29
2x+3=29
Let's subtract 3 from both sides.
2x=26
We divide both sides by 2
x=13
Now we add 3 to find the blue pens.
y=16
Therefore, Suzie has 16 blue pens.
I hope this helps!
