Respuesta :
D = DVDs
G = Games
Mike's formula 2D + 3G = 15.50
John's formula 3D + 1G = 12.05
If you multiple John by three and subtract from John you get the following.
-7D = -20.55
This is the same as 7D = 20.55
D = 2.94
Plugging that into John's, you get 3(2.94) + 1G = 12.05
8.82 + G = 12.05
G = 3.23
Answer: Cost of DVD is $2.95 and cost of games is $3.2.
Step-by-step explanation:
Let the cost of DVD be x
Let the cost of games be y
So, According to question,
[tex]2x+3y=\$15.50\\\\and\\\\3x+1y=\$12.05[/tex]
Now, we will apply " Substitution Method " i.e.,
[tex]2x=15.50-3y\\\\x=\frac{15.5-3y}{2}[/tex]
Put this value of x in second equation:
[tex]3x+y=12.05\\\\3\times \frac{15.5-3y}{2}+y=12.05\\\\46.5-9y+2y=12.05\times 2\\\\46.5-7y=24.1\\\\46.5-24.1=7y\\\\22.4=7y\\\\\frac{22.4}{7}=y\\\\3.2=y[/tex]
Now, substitute the value of y in equation of x:
[tex]x=\frac{15.5-3y}{2}\\\\x=\frac{15.5-3\times3.2}{2}\\\\x=\frac{15.5-9.6}{2}\\\\x=\frac{5.9}{2}\\\\x=2.95[/tex]
Hence, Cost of DVD is $2.95 and cost of games is $3.2.