# Thread: the average of a set....

1. ## the average of a set....

ok so here is the problem....

the average of a set of 8 consecutive odd integers is 18, what is the greatest of these integers?

this problems seems straight forward..

so i let x be my first integer and then counted out 7 more...

x, x+2, x+4, x+6 and so on...

i then added up the integers and got the setup to be

24.75, my book says the answer is 25. which i know is an integer, but i thought my approach was right. i just took my 8 integers and divided them by 8 and set it equal to 18? how did my book get 25 and what did i do wrong?

2. ## Re: the average of a set....

x + (x+2) + (x+4) .... + (x+14) = 8x + 56

(8x + 56) / 8 = 18
8(x + 7) / 8 = 18
x + 7 = 18
x = 11
So highest = x + 14 = 11 + 14 = 25

Were you tired?

3. ## Re: the average of a set....

yes i think i was or am a bit tired.....wow i cant believe i missed that. thanks for the correction.

Originally Posted by Wilmer
x + (x+2) + (x+4) .... + (x+14) = 8x + 56

(8x + 56) / 8 = 18
8(x + 7) / 8 = 18
x + 7 = 18
x = 11
So highest = x + 14 = 11 + 14 = 25

Were you tired?

4. ## Re: the average of a set....

Slow down by half, and get twice as much done...