A Math questions about radicals

Question

a object is moving at (3+sqrt(3))per second. How long does it take to go 20 feet

 

if you could show me how to do it that would be great (as in typing it out)

 

 

 

-bob

Answer 1

d = r · t

d / r = t

20 / (3 + √3) = t                 To rationalize the denominator, multiple numerator and denominator by 3 - √3

20(3 - √3) / (9 - 3) = t

20(3 - √3) / 6 = t

(60 - 20√3) / 6 = t

10 - (20√3)/6 = t