In a school of 309 kids, 28 kids are on the cross country team, 67 kids are on the track team, and 19 are on both. How many kids are on either cross country or track?

75

step-by-step explanation:

215.92 dollars is the answer

, 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

35-60 students are taking math.