Mr. Singer's choir is going to New York City for a choir competition. He wants them to look their best, so he buys new music folders for all of the members. Each music folder costs $7.99. If Mr. Singer buys 23 music folders, how much does he spend? (Please enter your answer without units.)

the answer is 183.77

Step-by-step explanation:

if you know the price was 7.99 for each one he bought you work multiply 23 by 7.99 and you get 183.77.

, 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

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x