View Full Version : Word problem polynomial f(x) help
1. The problem statement, all variables and given/known data
2 People build a sandcastle of 36cm by 48cm by 60cm. Later they learn that the box will be smaller; a certain amount will be taken off each of the length width and height
2. Relevant equations
3. The attempt at a solution
a) write a p(x)
> (36-x) (48-x) (60-x) , also x intercepts if (-x+36) = -(x-36) etc
b) graph (already did)
c) the amount of sand in the boc will be 3/5 of the amount in the design) , so i multiplied the l*w*h and then multiplied it by 3/5 and got the answer of 103,680 *3/5 = 62,208
d) How much was taken off each dimension? ( HOW DO I SOLVE THIS?) anyone? steps plz
epenguin
Sep24-11, 05:13 PM
any1?
Before the answer we'd need a question.
1. The problem statement, all variables and given/known data
2 People build a sandcastle of 36cm by 48cm by 60cm. Later they learn that the box will be smaller; a certain amount will be taken off each of the length width and height
2. Relevant equations
3. The attempt at a solution
a) write a p(x)
> (36-x) (48-x) (60-x) , also x intercepts if (-x+36) = -(x-36) etc
What do you mean, "write a p(x)" - A function that represents what?
Please give us the exact problem statement.
b) graph (already did)
c) the amount of sand in the boc will be 3/5 of the amount in the design) , so i multiplied the l*w*h and then multiplied it by 3/5 and got the answer of 103,680 *3/5 = 62,208
d) How much was taken off each dimension? ( HOW DO I SOLVE THIS?) anyone? steps plz
eumyang
Sep24-11, 09:08 PM
c) the amount of sand in the boc will be 3/5 of the amount in the design) , so i multiplied the l*w*h and then multiplied it by 3/5 and got the answer of 103,680 *3/5 = 62,208
d) How much was taken off each dimension? ( HOW DO I SOLVE THIS?) anyone? steps plz
Looks like you'll need to take p(x) and set it equal to 62,208:
(36 - x)(48 - x)(60 - x) = 62,208
However, unless you're allowed to solve it graphically using a graphing calculator, I'm not sure you can solve it algebraically (unless you know the cubic formula).
Um, Idk, the answer booklet says "approxmiately 9.28" , but yes im on d) and that is the function...
your method did not work
NascentOxygen
Sep24-11, 11:20 PM
If each dimension is reduced by 7.15 you get very close to the desired smaller volume.
eumyang
Sep25-11, 12:10 PM
Um, Idk, the answer booklet says "approxmiately 9.28" , but yes im on d) and that is the function...
your method did not work
Hmm, then either the answer booklet has a typo or you copied the problem wrong. I got the same answer that NascentOxygen got.
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