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Isaac downloaded 7 ringtones. Each polyphonic ringtone costs $3.25, and each standard ringtone costs $1.50. If he spends a total of $21 on ringtones, find the number of polyphonic and standard ringtones he downloaded.

Respuesta :

calculista

Answer:

[tex]6\ polyphonic\ ringtones[/tex]  and [tex]1\ standard\ ringtone[/tex]

Step-by-step explanation:

Let

x -----> the number of polyphonic ringtones

y ----> the number of standard ringtones

we know that

[tex]x+y=7[/tex]

[tex]x=7-y[/tex] -----> equation A

[tex]3.25x+1.50y=21[/tex] -----> equation B

Solve the system of equations by substitution

Substitute equation A in equation B and solve for y

[tex]3.25(7-y)+1.50y=21[/tex]

[tex]22.75-3.25y+1.50y=21[/tex]

[tex]3.25y-1.50y=22.75-21[/tex]

[tex]1.75y=1.75[/tex]

[tex]y=1\ standard\ ringtones[/tex]

Find the value of x

[tex]x=7-1=6\ polyphonic\ ringtones[/tex]

Answer:

6 polyphonic, 1 standard

Step-by-step explanation:

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