Question

3. You are looking into two long distance telephone plans offered by GT&T. The “One Rate 5 cents” plan has a monthly fee of $7.95 and all calls are 5 cents per minute. The “One Rate 7 cents” plan has a monthly fee of $4.95 and all calls are 7 cents per minute. Under what circumstances is one plan less expensive than the other?

a. The "One Rate 5 cents" plan is less expensive for calls lasting less than 1.5 minutes. The "One Rate 7 cents" plan is less expensive for calls lasting more than 1.5 minutes.

b. The "One Rate 7 cents" plan is less expensive for calls lasting less than 1.5 minutes. The "One Rate 5 cents" plan is less expensive for calls lasting more than 1.5 minutes.

c. The "One Rate 5 cents" plan is less expensive for calls lasting less than 150 minutes. The "One Rate 7 cents" plan is less expensive for calls lasting more than 150 minutes.

d. The "One Rate 7 cents" plan is less expensive for calls lasting less than 150 minutes. The "One Rate 5 cents" plan is less expensive for calls lasting more than 150 minutes.

Answer 1

D. After 150 minutes, the 5 cent one is more.

Hope this helps!

Answer 2

D.The "One Rate 7 cents" plan is less expensive for calls lasting less than 150 minutes. The "One Rate 5 cents" plan is less expensive for calls lasting more than 150 minutes.

Explanation:

let the total number of minutes of calls be x minutes.

Now let us find the total cost incurred in both plan for x mins.

Plan 5 cent : 7.95+0.05x

Plan 7 cent : 4.95+0.07x

Let us find the time at which both the plans will give you same Bill.

Hence

7.95+0.05x=4.95+0.07x

7.95-4.95=0.07x-0.05x

3=0.02x

x=150

Hence at 150th min, both the plan will charge you same cost. Hence the plan giving you less Bill for 100 mins will give you high Bill in 200 mins. Let us calculate the bill incurred by both plan at 100th min.

Plan 5 cent : 7.95+0.05×100=12.95

Plan 7 cent: 4.95+0.07×100=11.95

Hence plan 7 cent is lesser than 5 cent for calls more than 150 mins

Let find which plan cost you cheaper