Answer:
10 months
Explanation:
Let X represent the number of months
The cost equation for the first plan = $20 + 10x
The cost equation for the second plan =$ 40+8x
The number of months at which the cost for the two plans will be equal can be worked out by equating the costs for the two plans and then calculate the value of x.
Thus,
$20+10x = $40 +8x
10x -8x =$40-$20
2x = $ 20
x= 20/2
x= 10
Substituting X in each equation,
$20 +$10(10) = $40 + $8(10)
$ 20 +$100 =$40 +$80
$120 =$120
Thus, the amount after ten months = $120