all eighth grade student at school answered yes or no to the two survey question Shawn do you have a cell phone yes or no or do you have an MP3 player yes or no the results of the survey are shown in the table what percentage of the students have both a cell phone and an MP3 player. Need help please

any options?

step-by-step explanation:

, 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