The telephone rate of the two telecommunications companies A and B is calculated as follows every month.
A company : Base rate : 3500 yen
Telephone rate per minute : 25 yen
However, if telephone rate is less than 500 yen, only the base rate is charged.
As for the portion beyond 500 yen, 25 yen per minute is added to the base
rate.
B company : Base rate : 5000 yen
Telephone rate per minute : 20 yen
However, if telephone rate is less than 2500 yen, only the base rate is charged.
As for the portion beyond 2500 yen, 20 yen per minute is added to the base
rate.
(1) Display the graph of the relation of the call time and telephone rate of A company.
(2) Find the call time when the difference of the rate of A company and B company is 2000 yen.
Telephone rate per minute : 25 yen
However, if telephone rate is less than 500 yen, only the base rate is charged.
As for the portion beyond 500 yen, 25 yen per minute is added to the base
rate.
B company : Base rate : 5000 yen
Telephone rate per minute : 20 yen
However, if telephone rate is less than 2500 yen, only the base rate is charged.
As for the portion beyond 2500 yen, 20 yen per minute is added to the base
rate.
(1) Display the graph of the relation of the call time and telephone rate of A company.
(2) Find the call time when the difference of the rate of A company and B company is 2000 yen.
Answer
(1)
(2) 300 minutes
