The average of a and b is 2.5, the average of b and c is 3.8, and the average of a and c is 3.1. Find a, b and c.
Good luck!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2007-03-05 12:01:24 · 6 answers · asked by Anonymous in Pregnancy & Parenting ➔ Newborn & Baby
You have enough information for 3 equations. Since you know you get the "average" by adding the numbers and then dividing by how many numbers you added (for example if you add 1+3, that is 2 numbers so to find the average you divide by 2.... (1+3)/2.... or if you add 1+1+1 you'd divide by 3 etc.) so you get (a+b)/2=2.5 (b+c)/2=3.8 and (a+c)/2=3.1 ... now isolate any single variable... using the first equation: (a+b)/2=2.5, a+b=2(2.5), a=5-b... now that you have "a" in terms of "b" you need to get "c" in terms of "b"... rearrange the second equation to do this. (b+c)/2=3.8, b+c=(3.8)(2), c=7.6-b... now you have both "a" and c" in terms of "b" and you can subsitute these equations into the third original equation. (a+c)/2=3.1.... using the equations we just found (a=5-b and c=7.6-b) plug them in and you get: (5-b + 7.6-b)/2=3.1, (12.6-2b)/2=3.1, 12.6-2b=2(3.1), -2B=6.1-12.6, -2b=-6.5, b=(-6.5/-2), b=3.25, plug "b" into either of the 2 simple equations we found earlier i'll use c=7.6-b, c=7.6-3.25, c=4.35, and then plug c into the simple equation to find "a"... a=5-b, a=5-3.25, a=1.75... you can check these answers by plugging a,b, & c into the original 3 equations.and you'll see that it works!
2007-03-05 12:22:36 · answer #1 · answered by Anonymous · 0⤊ 0⤋
(a + b)/2 = 2.5
(b +c)/2 = 3.8
(a +c)/2 = 3.1
From the first equation, solve for a:
(a+b)/2 = 2.5
(a+b) = 5
a = 5 - b
From the second equation, solve for c:
(b + c)/2 = 3.8
b+c = 7.6
c = 7.6 -b
Substitute those values into the third equation:
(a+c)/2 = 3.1
(5-b + 7.6 - b)/2 = 3.1
5 - b + 7.6 - b = 6.2
12.6 - 2b = 6.2
6.3 - b = 3.2
b = 3.2/6.3
Substitute this into the first equation, and then substitute THAT answer into the second, and you'll have all three variables.
2007-03-05 20:09:09 · answer #2 · answered by Anonymous · 1⤊ 0⤋
I have no idea if Dances is right or not, but her answer sure looks good.
2007-03-05 20:13:24 · answer #3 · answered by Mommy...LT 3 · 0⤊ 0⤋
why is this in the parenting newborn section?
2007-03-05 20:05:30 · answer #4 · answered by Catlin 2 · 0⤊ 0⤋
wait so u don't have a question about your baby??
2007-03-05 21:45:09 · answer #5 · answered by ALL SMILES :D 5 · 0⤊ 0⤋
wrong category kiddo.
2007-03-05 20:10:43 · answer #6 · answered by sushishishi 5 · 0⤊ 0⤋