Answer:
The monthly change is $ 0.70
Step-by-step explanation:
From the statement, it can be seen that the average monthly change is $ 0.70. This can be derived from the following:
From 0 to 10 minutes, the difference was: $ 10.65 - $ 9.95 = $ 0.70
Then from 10 to 20 minutes, the difference was $ 11.35 - $ 10.65 = $ 0.70
In this way, the average difference was consistent throughout, that is, $ 0.70 increase in every 10 minutes.
Monthly cost of cell phone for 0 minutes is $19.95 and for 40 minutes of talk is $21.95.
It means that average rate of change ( increase of monthly cost for each minute of talk time ) is: ARC = ( 21.95 - 19.95 ) / ( 40 - 0 ) = 2.00 / 40 = $0.05.
Let us see...
y is the price.
y
Then, 18% off. This is:
y - (y*0.18) = 0.82*y
Then, we add 8%, so now it's 1.08% of this expression:
1, 000
2% · <em>x</em> = 20
0.02 · <em>x</em> = 20
20/0.02 = <em>x</em>
<em>x</em> = 1000
Double-Check:
1000 · 0.02 = 20
same question bro
