Question

the cost of a mobile phone call is 30 cents plus 20 cents per minute. Find the possible cost of a call if it is shorter than 5 minutes

Answer 1

The possible cost of a call if it is shorter than 5 minutes ranges between 30 cents and maximum 130 cents

Explanation:

Define a function as

Y: Cost of a call in cents

X: Number of minutes of call

So using the statement we can find that

Y=30+20X

because the cost of the call has a fix cost of 30 cents plus 20 cents per minute used. If the calls is shorter than 5 minutes for x = 5

Y=30+20X = 30 + (20*5) = 30 + 100 = 130 which is the cost of a call of max 5 minutes

Because you pay a fixed cost of 30 even if you spend very little time. X= 0 then the possible cost of a call if it is shorter than 5 minutes ranges between 30 cents and maximum 130 cents

Answer 2

The cost is less than $1.30

Explanation:

Let

y-----> the total cost of a mobile phone call

x----> the time in minutes

we know that

if time were x=5 minutes

the cost would be

y=0.30+0.20(5)=$1.30

but

the time is less than 5 minutes

therefore

the cost would be

y< $1.30