A dozen = 12.
Two dozen = 24
Set up a proportion:
![\frac{3 pens}{.99 cents} = \frac{24 pens}{X}](https://tex.z-dn.net/?f=%20%5Cfrac%7B3%20pens%7D%7B.99%20cents%7D%20%3D%20%20%5Cfrac%7B24%20pens%7D%7BX%7D%20)
Then we need to solve for X (the amount of money she paid)
Cross multiply to get 3x = 24(.99)
3x = 23.76
x= $7.92
Or you can do it another way if you knew 3 goes into 24 8 times, so you can multiply .99x8 = $7.92
2(x+4)=16
multiply the bracket by 2
(2)(x)=2x
(2)(4)=8
2x+8=16
move 8 to the other side, sign changes from +8 to -8
2x+8-8=16-8
2x=16-8
2x=8
divide both sides by 2 to get x by itself
2x/2=8/2
Answer:
x=4
I believe the answer is E.
Hope this helps!:)
P+A=420
P=6A
6A+A=420
7A=420
A=60
P=6(60)
P=360
CHECK:
P+A=420
360+60=420
420=420