You are buying decorations for a birthday party. The before-tax total for 3 rolls of crepe paper and 20 balloons is $11.40. After you start decorating, you need more supplies. You buy 2 more rolls of crepe paper and 10 more balloons for $7.20. How much did each roll of crepe paper and each balloon cost?

, 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

sadsdda

step-by-step explanation: