Tuesday

October 21, 2014

October 21, 2014

Posted by **vincecarl** on Saturday, November 5, 2011 at 2:52am.

- math -
**vincecarl**, Saturday, November 5, 2011 at 2:55amif 5 arithmetic means are inserted between 7 and 25 what is the middle mean to be inserted

- math -
**Reiny**, Saturday, November 5, 2011 at 6:10amThe multiples of 3 between 2 and 100 are

3, 6, 9, ... , 99 , an AS where a=3 and d=3

how many of those are there?

t(n) = a+(n-1)d

99 = 3 + (n-1)(3)

96 = 3n-3

99 = 3n

n = 33

so now you want the sum of those 33 arithmetic terms

S(33) = (33/2)(first + last) = (33/2)(3+99) = 1683

Your second question....

so your 7 becomes the first term, and your 25 becomes the 7th term

25 = 7 + 6d

d = 3

so your middle term would be term(4)

= a+3d = 7+9 = 16

check: 7 10 13**16**19 22 25

**Answer this Question**

**Related Questions**

maths - find the number of integers between 32 and 395 that are divisible by 6 ...

discrete math - Find how many positive integers with exactly four decimal digits...

Discrete Structures - a. Show that in any set of n integers, there is a subset ...

college math - I do not understand a problem from a text book or how to solve ...

Math - How many Positive integers are between 200-500 that are divisible by the ...

Math - How many Positive integers are between 200-500 that are divisible by the ...

MATHEMATICS_algebra - How many integers between 100 and 200 are divisible by 6...

Math - Divisibility and Factors - If c and d are integers, d is divisible by 30...

teaching math - Indicate whether the deductive reasoning used is an example of ...

teaching math - Indicate whether the deductive reasoning used is an example of ...