Question

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.

Answer 1

Answer:

$6\ polyphonic\ ringtones$  and $1\ standard\ ringtone$

Step-by-step explanation:

Let

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

y ----> the number of standard ringtones

we know that

$x+y=7$

$x=7-y$ -----> equation A

$3.25x+1.50y=21$ -----> equation B

Solve the system of equations by substitution

Substitute equation A in equation B and solve for y

$3.25(7-y)+1.50y=21$

$22.75-3.25y+1.50y=21$

$3.25y-1.50y=22.75-21$

$1.75y=1.75$

$y=1\ standard\ ringtones$

Find the value of x

$x=7-1=6\ polyphonic\ ringtones$

Answer 2

Answer:

6 polyphonic, 1 standard

Step-by-step explanation: