The family fine arts center charges $21 per adult and $13 per senior citizen for its performances. on a recent weekend evening when 535 people paid admission, the total receipts were $8355. how many who paid were senior citizens?
i am struggling with the right formula to use.
do i use an arthimetic or geometric sequence?

175 adults

360 senior citizens

Step-by-step explanation:

Let x be the number of senior citizens

There were a total of 535 people, so

(535-x)=total number of adults

Total receipts=$8,355

Adult payments+Senior payments=$8,355

21(535-x)+13x=$8,355

$11,235-21x+13x=$8,355

$11,235-8x=$8,355

-8x=$-2,880

x=360 senior citizens

Number of adults=535-360=175 adults

To check, just substitute...

21(175)+13(360)

3,675+4,680

Which equals

$8,355

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,