Comparing two pay scales

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Question from san, a student:

Mable is offered a job selling magazine subscriptions. She has the choice of two pay scales.
Pay scale 1:
She can be paid $0.65 for each subscription she sells.
Pay scale 2:
She can be paid $0.10 for the first subscription, with the wage gong up $0.05 more for each subscription after the first.
For her first sale she would make $0.10, for her second sale she would make $0.15, for her third sale she would make $0.20, and so on.
Please compare and analyze the two scales. Which scale is better?

Hi San,

I would analyze the two choices using a table. I used I to indicate the first pay scale and II to indicate the second. The total columns keep track of your total income as you sell more subscriptions.

Number sold	I: $	II: $	I: total	II: total
1	0.65	0.10	0.65	0.10
2	0.65	0.15	1.30	0.25
3	0.65	0.20	1.95	0.45
4	0.65	0.25	3.60	0.70
5	...	...	...	...

Expand the table for a few more rows. When does the II:$ column get to $0.65? Will the II:total column ever pass the I:total column? Which pay scale is better is a decision you will have to make. Your answer will need some explanation.

Penny

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