Calculating Annual Saving: Word Problem

[emmayu]

Hi, guys, I could not figure out the answer to this Q, no matter how hard I did this math. I know this should not be a difficult one, but really my answer never matched the correct one. Please do help me on how to get the answer? Many thanks!

 

[Sudharaka]

Hi, guys, I could not figure out the answer to this Q, no matter how hard I did this math. I know this should not be a difficult one, but really my answer never matched the correct one. Please do help me on how to get the answer? Many thanks!
View attachment 800

Hi emmayu, :)

Welcome to MHB! I feel that there is a mistake or something missing in this question. What confuses me most is why the problem mentions an annual fee as well as a monthly fee for each of the network plans.

Annual fee for Gem plan is, 54.99. Note that the customer uses an excess of 50 mins each month for mobile (same network) and mobile (other network) calls. That is if he uses Gem plan he has to pay 50*0.25 + 50*0.30 each month for the excess minutes he used. That constitutes to a 12*(50*0.25 + 50*0.30) annual fee. So the total fee for using the Gem plan is 54.99 + 12*(50*0.25 + 50*0.30) = 384.99 annually.

Since this customer uses the Gem plan we can conclude that he uses 200 mins(same network) and 200 mins(other networks) monthly. Therefore for the Royale plan we get, 59.49 + 12*100*0.32=443.49 annual fee.

So the saving for using the Gem plan is, 443.49-384.99=58.5 which isn't among the answers.

All the above currency amounts are given in pounds.