question from flash card

[MOONSUNY140]

Hello, I found this following problem on the flash cards.
I dont understand on the answer sheet, why express (r-50,000) why subtract 50,000 from r?

Is the statement sufficient?
Carla earns a base salary of $30,000 plus 10% commission
on her total sales revenue exceeding $50,000. How much
did she make on commission this year?

1) If her total sales revenue had been 25% higher, her
commission would have been 20% higher

First, label total commission c and total sales revenue r. The
key is to realize that we have 2 different ways to express the
relationship between our two variables. From the question,
we know that c = 0.1(r – 50,000). From the statement, we
know that 1.2c = 0.1(1.25r – 50,000). We know that we have
2 linear equations relating our 2 variables, so we will get one
unique solution.

[RonPurewal]

Carla earns a base salary of $30,000 plus 10% commission
on her total sales revenue exceeding $50,000.

the blue thing is the reason for subtracting 50,000. "the revenue in excess of $50,000" doesn't count the first $50,000.

e.g., if her sales are $77,000, then her commission is %10 of 27,000 (not 77,000).

[RonPurewal]

this is the wrong folder for your query, by the way, so this thread is now locked. if you have further questions about this item, please post a thread in the correct folder (MGMAT non-CAT math).
thanks.