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Paul is comparing the cost of cell phone services. At CellCoA, the phone he wants costs $305 and the unlimited calling plan costs $45 per month. At CellCoB, Paul can purchase the same phone for $350 and get an unlimited calling plan for $30 per month. In how many months will both plans cost the same? These equations, which are graphed below, represent the situation. y = 45x + 305 y = 30x + 350 Here, x represents the number of months and y represents the amount paid.

User Nshmura
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2 Answers

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In 3 months the cost will be the same, they will both cost $440, A is expressed as Cost = 305 + 45m (months) while B is expressed as Cost = 350 +30m because their cost will be the same equation A will equal equation B, 305 +45m = 350 +30m, subtract 30m from both sides to get 305+15m = 350, then subtract 305 from both sides to get 15m = 45, divide by 15 to get m to get m=3 which equals to x=3 input x in both equations to get your y, y = 45(3) + 305 and y= 30(3) + 350, they both give you the answer y= 440 so the point they intersect at is (3,440)
User Shimon Wiener
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3 votes

Answer: There are 3 months in which both plans cost the same.

Explanation:

Since we have given that

Two equations are given below:


y = 45x+305\\\\y = 30x+350

Since both the equations equal to y.

So, it becomes


45x+305=30x+350\\\\45x-30x=350-305\\\\15x=45\\\\x=(45)/(15)\\\\x=3

Here, x represents the number of months.

Hence, there are 3 months in which both plans cost the same.

User Josh Kupershmidt
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6.2k points
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