the mean height of a girl and 6 boys is 168cm. The mean height of 6 boys is 172cm. What is the height of the girl?
2007-03-04 00:43:33 · 5 answers · asked by Sinead K 2 in Education & Reference ➔ Homework Help
total ht of G+6B
= 168 x 7
= 1176
total ht of 6B
= 172 x 6
=1032
ht of girl
= 1176 - 1032
= 144!
2007-03-04 01:11:32 · answer #1 · answered by befuzzy87 2 · 0⤊ 0⤋
my guess is 144cm.
If the mean height of the 7 people is 168cm.
the total height would be 7x168=1176cm
Total Height of the 6 boys would be 6x172=1032cm
That leaves the girl, which height 1176-1032= 144cm.
Hope thats the right answer!! Correct me if i'm wrong!!
2007-03-04 08:53:13 · answer #2 · answered by Frost 3 · 0⤊ 0⤋
Okay here goes...
Let G = girl's heigt
Let B = boys average height
Equation#1: (G + 6B) / 7 = 168
Equation #2: 6B / 6 = 172
By Equation #2, B = 172
So...
By Equation#1: (G + 6 (172) ) / 7 = 168 [Substitution]
(G + 1032) / 7 = 168 [Simplify]
G + 1032 = 7(168) [Simplify]
G + 1032 = 1176 [Simplify]
G = 144 cm [Subtract 1032 from both sides]
2007-03-04 09:05:14 · answer #3 · answered by Friend_88 3 · 0⤊ 0⤋
140
2007-03-04 11:39:19 · answer #4 · answered by pooja 2 · 0⤊ 0⤋
140cm
2007-03-04 08:51:29 · answer #5 · answered by You-Know-Who 2 · 0⤊ 0⤋