Question

13) 3 bags of Brand X dog food and 4 bags of Brand Y dog food costs $18,

Answer 1

Answer:

the cost of brand x dog food is $2

Step-by-step explanation:

Let brand X dog food be represented as A

Let Brand Y dog food be represented as B

3 bags of Brand X dog food and 4 bags of Brand Y dog food costs $18,

3A+4B=18

4 bags of Brand X dog food and 3 bags of Brand Y dog food costs

$17.

4A+3B= 17

• 3A+4B=18
• 4A+3B= 17

Using Elimination method

Multiply

• 3A+4B=18 by coefficient of B in equ ii (3)  = 9A+12B=54

• 4A+3B= 17 by coefficient of B in equ i (4)  = 16A+12B=68
• subtract equation i from equation ii, since sign is the same in both equations
• 9A+12B-(16A+12B)= 54-68
• open bracket

• 9A+12B-16A-12B= 54-68= -14
• 9A-16A+12B-12B= -14
• -7A= -14
• divide both sides by -7

A = -14/-7= 2

Since the brand X dog food is represented as A

the cost of brand x dog food is $2