MATH SOLVE

2 months ago

Q:
# Please help with algebra problem

Accepted Solution

A:

Number of weekend minutes used: x

Number of weekday minutes used: y

This month Nick was billed for 643 minutes:

(1) x+y=643

The charge for these minutes was $35.44

Telephone company charges $0.04 per minute for weekend calls (x)

and $0.08 per minute for calls made on weekdays (y)

(2) 0.04x+0.08y=35.44

We have a system of 2 equations and 2 unkowns:

(1) x+y=643

(2) 0.04x+0.08y=35.44

Using the method of substitution

Isolating x from the first equation:

(1) x+y-y=643-y

(3) x=643-y

Replacing x by 643-y in the second equation

(2) 0.04x+0.08y=35.44

0.04(643-y)+0.08y=35.44

25.72-0.04y+0.08y=35.44

0.04y+25.72=35.44

Solving for y:

0.04y+25.72-25.72=35.44-25.72

0.04y=9.72

Dividing both sides of the equation by 0.04:

0.04y/0.04=9.72/0.04

y=243

Replacing y by 243 in the equation (3)

(3) x=643-y

x=643-243

x=400

Answers:

The number of weekends minutes used was 400

The number of weekdays minutes used was 243

Number of weekday minutes used: y

This month Nick was billed for 643 minutes:

(1) x+y=643

The charge for these minutes was $35.44

Telephone company charges $0.04 per minute for weekend calls (x)

and $0.08 per minute for calls made on weekdays (y)

(2) 0.04x+0.08y=35.44

We have a system of 2 equations and 2 unkowns:

(1) x+y=643

(2) 0.04x+0.08y=35.44

Using the method of substitution

Isolating x from the first equation:

(1) x+y-y=643-y

(3) x=643-y

Replacing x by 643-y in the second equation

(2) 0.04x+0.08y=35.44

0.04(643-y)+0.08y=35.44

25.72-0.04y+0.08y=35.44

0.04y+25.72=35.44

Solving for y:

0.04y+25.72-25.72=35.44-25.72

0.04y=9.72

Dividing both sides of the equation by 0.04:

0.04y/0.04=9.72/0.04

y=243

Replacing y by 243 in the equation (3)

(3) x=643-y

x=643-243

x=400

Answers:

The number of weekends minutes used was 400

The number of weekdays minutes used was 243