Given:
Total cost of the call = $7.75
The charge for the first minute was $ 1. Each extra minute cost $ 0.25.
To find:
The equation for this situation and the call duration.
Solution:
Let x be the call duration in minutes.
Remaining minutes after first one minute = x-1
Cost of first minute = $1
Cost of 1 extra minute = $0.25
Cost of (x-1) extra minutes = $0.25(x-1)
Total cost of call = Cost of first minute + Cost of extra minutes
[tex]7.75=1+0.25(x-1)[/tex]
[tex]7.75=1+0.25x-0.25[/tex]
[tex]7.75=0.25x+0.75[/tex]
[tex]7.75-0.75=0.25x[/tex]
[tex]7=0.25x[/tex]
Divide both sides by 0.25.
[tex]\dfrac{7}{0.25}=x[/tex]
[tex]28=x[/tex]
Therefore, the required equation is [tex]7.75=1+0.25(x-1)[/tex] and call duration is 28 minutes.
