The bottom and top of a box are rectangles twice as long as they are wide. Find the volume of the box if it is 4 ft high and has a total surface area of 220 ft2. Which equation can be used to solve this problem?
A.
4w2 + 8w = 220
B.
4w2 16w = 220
C.
4w2 + 24w = 220
D.
4w2 24w = 220
2007-01-04 08:31:01 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The width is w
The length is 2w
The height is 4
Surface area would be 6 sides
2 with areas of w * 2w
2 with areas of 2w * 4
2 with areas of 4w
So 2(2w² + 8w + 4w), which reduces to:
4w² + 24w = 220
The answer is c.
Note: to solve the problem further, you would get everything on the left.
4(w² + 6w - 55) = 0
Then you would factor:
4(w + 11)(w - 5) = 0
w = -11 or w = 5
Since the negative length makes no sense, the answer would be that the width was 5, the length was 10 and the height was 4. As a double-check. 5x10 = 50, 10x4 = 40, 5x4 = 20. 2(50+40+20) = 220.
Anyway, the answer is:
c) 4w² + 24w = 220
2007-01-04 08:34:20 · answer #1 · answered by Puzzling 7 · 1⤊ 0⤋
the question is: whats the volume?
solving equation C
4w^2+24w=220
we have w=5
so 5*2*5*4=200cft
2007-01-04 16:48:34 · answer #2 · answered by j 3 · 0⤊ 0⤋
4w^2+24w=220
2007-01-04 16:38:25 · answer #3 · answered by raj 7 · 0⤊ 0⤋