Test. Mobile phones

Before proceeding to the solution of examples and problems be sure to read the theoretical part of the lesson 

Mobile phones

Compare these two tariffs.

The best choice depends on how many minutes are used.

 1. 20 minutes on tariff P would cost 20 × 4p = 80p. Copy and complete this table for tariff P.

 а)  4,  8,  10,  16;     

 b)  4,  8,  12,  16;     

 c)  4,  8,  12,  18;     

 d)  4,  6,  12,  16.

 2. 20 minutes on tariff Q would cost £9, then add on (20 × 1p) which is £0.20. 20 minutes cost £9.20.

 а)  9.50,  10,  11,  12,  13;     

 b)  9,  10,  11.50,  12,  13;     

 c)  9,  10.50,  11,  12,  13;     

 d)  9,  10,  11,  12,  13.50.

Copy the axes opposite onto squared paper. Plot points from the tariff P table and join them up to make a straight line. Plot points from the tariff Q table using the same axes as before. Join them up to make a straight line. Your graph should look like this.

 3. After how many minutes do the 2 lines cross?

 а)  290;      
 b)  280;     

 c)  320;      
 d)  300.

 4. What is the cost on both tariffs when the 2 lines cross?

 а)  10;      
 b)  8;     

 c)  12;      
 d)  16.

 5. If the number of minutes you use your mobile phone is less that your answer to Question 3, which tariff is cheaper for you?

 а)  tariff  P;      
 b)  ;     

 c)  tariff  Q;      
 d)  .

 6. If the number of minutes you use your mobile phone is more that your answer to Question 3, which tariff is cheaper for you?

 а)  ;      
 b)  tariff  P;     

 c)  ;      
 d)  tariff  Q.

Compare these two tariffs.

The best choice depends on how many minutes are used.

 7. 20 minutes on tariff Z would cost 20 × 4.5p = 90p. Copy and complete this table for tariff P.

 а)  4,5,  9,  13,  18;     

 b)  4,5,  9,  13,5,  18;     

 c)  4,5,  9,  13,  18,5;     

 d)  4,  9,5,  13,5,  18.

 8. 20 minutes on tariff Y would cost £5, then add on (20 × 2p) which is £0.40. 20 minutes cost £5.40.

 а)  6,  7,  9,  11,  13;     

 b)  6,  7,  9,  10,  13;     

 c)  6,  7,  8,  11,  13;     

 d)  6,  7,  9,  11,  15.

Copy the axes opposite onto squared paper. Plot points from the tariff P table and join them up to make a straight line. Plot points from the tariff Q table using the same axes as before. Join them up to make a straight line. Your graph should look like this.

 9. After how many minutes is the cost the same for both tariffs?

 а)  200;      
 b)  240;     

 c)  180;      
 d)  210.

10. Which tariff would you advise if you use your mobile phone for 150 minutes?

 а)  tariff  Y;      
 b)  ;     

 c)  tariff  Z;      
 d)  .

11. Which tariff would you advise if you use your mobile phone for 320 minutes?

 а)  ;      
 b)  tariff  Y;     

 c)  ;      
 d)  tariff  Z.