Question

ron bought 8 pencils and 2 erasers for $1.66. Sarah bought 12 pencils and 5 erasers for $3.19. What is the cost for one pencil and one eraser

Answer 1

Use p for pencils and e for erasers.
8p+2e=1.66
12p+5e=3.19
Solve by elimination. To do that, multiply the first equation by 5 and the second equation by -2. The equations are now:
40p+10e=8.30
-24p-10e=-6.38
Combine the equations to simplify.
16p=1.92
Divide each side by 16
p=0.12
Each pencil costs $0.12
Plug that back into an equation:
8(0.12)+2e=1.66
Simplify
0.96+2e=1.66
Simplify
2e=0.7
Simplify
e=0.35
Each eraser costs $0.35
ANSWER: Pencils cost $0.12 each, and erasers cost $0.35.
A thanks and 5 star is always appreciated :D :D :D

Answer 2

Well just start to divide.
1.66/8=0.207
1.66/2=0.83

Now the next.
3.99/12=0.332
3.99/5=0.798

Ron :
Pencil - 0.207 cents
Eraser - 0.83 cents

Sarah :
Pencil - 0.332 cents
Eraser - 0.798 cents

Hoped I helped!