SOLUTION: The function D(t)=18t2−130t gives the distance a car going a certain speed will skid in t seconds. Find the time it would take for the car to skid 150 feet.

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: The function D(t)=18t2−130t gives the distance a car going a certain speed will skid in t seconds. Find the time it would take for the car to skid 150 feet.      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1195776: The function D(t)=18t2−130t gives the distance a car going a certain speed will skid in t seconds. Find the time it would take for the car to skid 150 feet.
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

D%28t%29=18t%5E2%E2%88%92130t
given: D%28t%29=150 feet
150=18t%5E2%E2%88%92130t
0=18t%5E2%E2%88%92130t-150.......use quadratic formula
t+=+%28-%28-130%29+%2B-+sqrt%28+%28-130%29%5E2-4%2A18%2A%28-150%29+%29%29%2F%282%2A18%29+
t+=+%28130+%2B-+sqrt%28+27700+%29%29%2F36+
t+=+%28130+%2B-+10sqrt%28277%29%29%2F36+

exact solutions:
t+=+%28130+%2B10sqrt%28277%29%29%2F36+ -> t=65%2F18+%2B+%285sqrt%28277%29%29%2F18
or
t+=+%28130+-+10sqrt%28277%29%29%2F36+->t=65%2F18+-%285sqrt%28277%29%29%2F18

approximately:
t=8.23+ seconds
or
t=-1.012032493637-> disregard negative solution, time cannot be negative

so, the time it would take for the car to skid 150 feet is approximately 8.23+ seconds



Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
.

As the problem is posed,  it is nonsense,  since the given function is  NEGATIVE

at   0 < t < 130%2F18 = 7.22...   seconds,  and  CAN  NOT  represent traveled distance,

which is always positive,  due to meaning of this conception/notion.



Keeping it in mind,  ignore the solution from the other tutor,
for safety of your brain.