28.03.2020

Sal is trying to determine which cell phone and service plan to buy for his mother. the first phone costs $100 and $55 per month for unlimited usage. the second phone costs $150 and $51 per month for unlimited usage. how many months will it take for the second phone to be less expensive than the first phone?

the inequality that will determine the number of months, x, that are required for the second phone to be less expensive is .

the solution to the inequality is .

sal’s mother would have to keep the second cell phone plan for at least months in order for it to be less expensive.

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Step-by-step answer

17.02.2022, solved by verified expert
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64 students found this answer . helpful

 13 months.

Step-by-step explanation:

First phone:

f(x)= cost of the first phone

x=number of months

f(x)=55x+100

Second phone:

g(x)=cost of the second phone.

x=number of months.

g(x)=51x+150

Therefore:

The inequality that will determine the number of months, x, that are required for the second phone to be less expensive is:

g(x)<f(x)

51x+150<55x+100

 51x+150<55x+100

The solution to the inequality is: 

51x+150<55x+100

51x-55x<100-150

-4x<-50

-x<-50/4

-x<-12.5

x>12.5

x>12.5 months                   (x>13)

Sal’s mother would have to keep the second cell phone plan for at least months in order for it to be less expensive.

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Faq

Mathematics
Step-by-step answer
P Answered by PhD
First phone:
f(x)= cost of the first phone
x=number of months

f(x)=55x+100

Second phone:
g(x)=cost of the second phone.
x=number of months.

g(x)=51x+150

Therefore:
The inequality that will determine the number of months, x, that are required for the second phone to be less expensive is:

g(x)<f(x)

51x+150<55x+100

 51x+150<55x+100

The solution to the inequality is: 
51x+150<55x+100
51x-55x<100-150
-4x<-50
-x<-50/4
-x<-12.5
x>12.5

x>12.5 months                   (x>13)

Sal’s mother would have to keep the second cell phone plan for at least months in order for it to be less expensive.

 13 months. 
Mathematics
Step-by-step answer
P Answered by PhD

a) The first inequality 100+55x>150+51x;

b) The last inequality x>12.5

c) 13 months

Step-by-step explanation:

a) Let x be the number of months.

1. The first phone costs $100 and $55 per month for unlimited usage, then for x months it will cost $55x and in total

$(100+55x)

2. The second phone costs $150 and $51 per month for unlimited usage, then for x months it will cost %51x and in total

$(150+51x)

3. If the second phone must be less expensive than the first phone, then

150+51x<100+55x

or

100+55x>150+51x

b) Solve this inequality:

55x-51x>150-100

4x>50

x>12.5

c) Sal's mother has to keep the second cell phone for at least 13 months (because x>12.5).

Mathematics
Step-by-step answer
P Answered by PhD

SI=(P*R*T)/100

P=2000

R=1.5

T=6

SI=(2000*1.5*6)/100

=(2000*9)/100

=180

Neil will earn interest of 180

Mathematics
Step-by-step answer
P Answered by PhD

Cost of 7 gallons=$24.50

Cost of 1 gallon=24.50/7=3.5

Cost of 15 gallons=15*3.5=52.5

Cost of 15 gallons will be $52.5

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