If you would like to know the cost of one kilogram of each type of a candy, you can calculate this using the following steps:
1 kilogram of cinnamon red hots ... x = ?
3 kilograms of cinnamon red hots ... 3 x = ?
1 kilogram of gummy bears ... y = ?
3 kilograms of gummy bears ... 3 y = ?
Erika: 3 x + y = $21.00
Irene: 3 * x + 3 * y = $39.00
3 x + y = 21
3 x + 3 y = 39
_________________
3 x + y - (3 x + 3 y) = 21 - 39
3 x + y - 3 x - 3 y = - 18
- 2 y = - 18 /(-2)
y = $9
3 * x + y = $21.00
3 x = 21 - y
3 x = 21 - 9
3 x = 12 /3
x = $4
The correct result would be: 1 kilogram of cinnamon red hots cost $4 and 1 kilogram of gummy bears cost $9.
