Your student class council needs $600 for the Winter Dance. With only $210 in their treasury, the council decided to raise the rest by selling donut coupons for a profit of $1.50 per dozen. Write and solve an equation to find how many donut coupons they will need to sell

$390

Step-by-step explanation:

Need: 600        

Have: 210         600-210=390          

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for