Respuesta :
Answer:
- Both the hat and mask cost $1
Step-by-step explanation:
Let the cost of each hat is x and each mask is y.
According to the question, set the equations:
- 10x + 20y = 30
- 8x + 10y = 18
Double the second equation and subtract the first one:
- 8x*2 + 10y*2 - 10x - 20y = 18*2 - 30
- 16x - 10x = 36 - 30
- 6x = 6
- x = 1
Find the value of y:
- 10*1 + 20y = 30
- 20y = 30 - 10
- 20y = 20
- y = 1
- hats be h and masks be m
Equations are
- 10h+20m=30=>h+2m=3--(1)
- 8h+10y=18=>4h+5m=9--(2)
Eq(1)×4
[tex]\\ \tt\hookrightarrow 4h+8m=12\dots(3)[/tex]
Subtract (3) and (2)
[tex]\\ \tt\hookrightarrow 3m=3[/tex]
[tex]\\ \tt\hookrightarrow m=1[/tex]
Put in eq(1)
[tex]\\ \tt\hookrightarrow h+2=3[/tex]
[tex]\\ \tt\hookrightarrow h=1[/tex]