Question

Sara is twice as tall as Willie ans 2/3 as tall as Andre.If the average height of all three is 4 ft.how tall is Andre?
a.2ft b.4ft c.5ft d.ft e.8ft

Answer 1

Well, make Sara's height S, Willie's height W, and Andre's height A. I'm assuming that you meant Sara is twice Willie's height AND 2/3 Andre's height. This means: S= 2*W and S=2/3*A

This means that W=S/2=2/3*A/2=A/3 and that S=2/3*A
The average of their heights is thus (S+W+A)/3=(A/3+2/3*A+A)/3 or 2A/3
Since the average height is 4 ft, 2A/3=4 feet. Solve for A:
A=6 feet.

I don't see that as an option, but I'm guessing d. was 6 feet, which would be your answer.

Answer 2

4ft

Answer 3

S=2W
S=(2/3)A

HENCE
W = S/2
A = (3/2)S

AVERAGE OF ALL IS 4

HENCE
(W+A+S)/3 = 4
((S/2)+((3/2)S)+S)/3=4
(S+3S+2S)/6=4
6S/6=4

So S=4
W=8
A =6

Answer 4

/\ rahulpn25,
If W=S/2, then how does W=8 when S=4?

Using your method, S=4, so W=2,.

Whatever the case, you still come out with A=6, which is what they're looking for. They're looking for ANDRE's height, not Sara's. Therefore, as you proved, andre's height is 6 feet.