Help with my maths schoolwork ("Sarah's Phone": 9 Qs in sideways pictures)

[HateMaths]

Hello everyone. I really am hoping that you people will be able to help me. I’ve got 3 pictures to send you.

 

[Dr.Peterson]

Are you asking us to do your work for you? That's not what we do:

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Please follow the guidelines by showing what you have done, or asking specific questions, so we can help you learn. Then you'll be able to solve these problems (and earn the credit) yourself.

(The little you wrote is not what they asked for. When they asked for an equation, you wrote an expression.)

 

[topsquark]

Hello everyone. I really am hoping that you people will be able to help me. I’ve got 3 pictures to send you. View attachment 35107
View attachment 35108
View attachment 35109

In addition, please post only one question per thread. Something like this is going to end up being too confusing.

-Dan

 

[Otis]

Section 2 – Sarah's got a phone problem… (13 marks)

Sarah's current mobile phone plan is about to end. She is currently with Telstra and has 80 GB of data left. She is deciding between two options:

Option 1
Continue to recharge with Telstra. If she chooses this option, the 80 GB of data left rolls over into the next recharges.

Option 2
Change to Optus which offers more data at the same price, but does not roll over the 80 GB of data she has left.

For both prepaid plans, she does not enable auto-recharging.

Let m represent the number of months that Sarah recharges her prepaid plan and Dr represent the amount of mobile data available after each recharge with Telstra.

Using these variables, write an equation that shows the relationship between the number of recharges and data available if Sarah continues to recharge with Telstra.

I need help understanding this exercise. I'm able to write an equation relating variables m and Dr, but it would be valid only after the first recharge (m=1). After that, I'm not sure what to do; it seems like I'd need info about data usage. I must be missing something. ?
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