There are five #s: a, b, c, d & x. The mean of a, b, c, & d is 80. If the mean of all five #s is 120, what is x?
2006-10-18 11:07:57 · 4 answers · asked by gigi_victory 3 in Science & Mathematics ➔ Mathematics
(a+b+c+d)/4=80
a+b+c+d=320
(a+b+c+d+x)/5=120
a+b+c+d+x=600
x=(a+b+c+d+x)-(a+b+c+d)=600-320=280
2006-10-18 11:11:59 · answer #1 · answered by yupchagee 7 · 16⤊ 0⤋
Yupchagees is right except he left off a zero.
(a+b+c+d)/4=80
a+b+c+d=320
(a+b+c+d+x)/5=120
a+b+c+d+x=600
x=(a+b+c+d+x)-(a+b+c+d)=600-32...
Should be (last line)
x = (a+b+c+d+x)-(a+b+c+d) = 600 - 320 = 280
Yupchagee probably did this on purpose because he didn't want to do EVERYTHING for you.
2006-10-18 18:17:10 · answer #2 · answered by Anonymous · 0⤊ 0⤋
40
2006-10-18 18:46:41 · answer #3 · answered by blackbeltcc4 2 · 0⤊ 0⤋
The mean of a,b,c and d is 80
Therefore their total value is 80x4+320
Now the mean of a,b,c,d and x is 120
Therefore their total value is 120x5=600
Deducting the total value of a,b,c,d (320) from the total value of a,b,c,d and x(600) leaves 280 which is the value of x
2006-10-18 18:24:13 · answer #4 · answered by Prabhakar G 6 · 0⤊ 0⤋