## Two word problems

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
Writ
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Joined: Tue Oct 23, 2012 5:29 pm
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### Two word problems

Can anyone explain how to work these? I'm completely lost. Thanks!

1. An object is launched from a platform that is 256 feet above the ground. The height, s, of the
object above the ground t seconds after it is launched is given by the formula s = -16t^2 + 96t + 256

a) What is the height of the object after 2 seconds?
b) How long will it take for the object to hit the ground?
c) When will the object be at a height of 256 feet?

2. A homeowner has installed an in-ground pool in the backyard. The pool is rectangular in
shape, with a length that is 4 feet more than its width. The homeowner put a one-foot-wide concrete
border around the pool. If the area covered by the pool and the border is 96 square feet, find the
dimensions of the pool.

little_dragon
Posts: 226
Joined: Mon Dec 08, 2008 5:18 pm
Contact:

### Re: Two word problems

Can anyone explain how to work these? I'm completely lost. Thanks!

1. An object is launched from a platform that is 256 feet above the ground. The height, s, of the
object above the ground t seconds after it is launched is given by the formula s = -16t^2 + 96t + 256

a) What is the height of the object after 2 seconds?
b) How long will it take for the object to hit the ground?
c) When will the object be at a height of 256 feet?
a) plug in the number they give you for t and solve for s
b) plug in the height s=0 for "the ground" and solve for t
c) plug in the number for height and solve for t
2. A homeowner has installed an in-ground pool in the backyard. The pool is rectangular in
shape, with a length that is 4 feet more than its width. The homeowner put a one-foot-wide concrete
border around the pool. If the area covered by the pool and the border is 96 square feet, find the
dimensions of the pool.
draw a picture w/ 2 rectangles (1 inside the other)
label w/ w, w+4, w+1+1, w+4+1+1
do area eqn
set equal to 96
solve
its like what they show halfway down here: http://www.purplemath.com/modules/perimetr2.htm
but w/ rectangles instead of circles

plz rite back if ur stuck
thx