Question

Emily is shopping at the toy store. In that store all dolls are sold at the same price and all dresses are sold at the same price. If Emily buys one doll and one dress, it will cost her $21.00. If Emily buys two dolls and three dresses, it will cost her $51.00. What is the price of one doll at that store?​

Answer 1

$12.

Explanation:

1) if price of one doll is 'x', of one dress is 'y', then the condition 'buys one doll and one dress, it will cost her $21.00' can be written as x+y=21;

2) the condition 'buys two dolls and three dresses, it will cost her $51.00' can be written as 2x+3y=51;

3) it is possible to make up the system:

`\left \{ {{x+y=21} \atop {2x+3y=51}} \right. \ = > \ \left \{ {{x=12} \atop {y=9}} \right.`

4) the price of one doll is 12$.