Answer:
Step-by-step explanation:
Let
p = number of pencil
r = number of ruler
e = Number of eraser
Six pencils are equal in value to two rulers.
6p = 2r
Divide both sides by 2 to get r
r = 6p / 2
= 3p
r = 3p
One ruler is equal in value to two erasers.
r = 2e
Recall r = 3p
Therefore, r = 3p = 2e
Twelve pencils are equal in value to a0 erasers.
3p = 2e
To get 12 pencils, multiply both sides by 4
4(3p) = 4(2e)
12p = 8e
12 pencils = 8 erasers
b. 2 erasers are equal to a1 pencils
Recall,
3p = 2e
2 erasers are equal to 3 pencils
c. 1 ruler and 4 erasers are equal to a2 pencils
3p = r = 2e
r + 4e
Multiply 2e by 2 to get 4erasers
= 3p + 2(2e)
Recall, 2e = 3p
= 3p + 2(3p)
= 3p + 6p
= 9p
1 ruler and 4 erasers = 9 pencils