help please. medal.
the time t required to drive a certain distance varies inversely with the speed, r. if it takes 4 hours to drive the distance at 40 miles per hour, how long will it take to drive the same distance at 55 miles per hour?
a. about 2.91 hours
b. about 160.00
c. 22.00 hours
d. about 5.50 hour

Question

help please. medal.
the time t required to drive a certain distance varies inversely with the speed, r. if it takes 4 hours to drive the distance at 40 miles per hour, how long will it take to drive the same distance at 55 miles per hour?
a. about 2.91 hours
b. about 160.00
c. 22.00 hours
d. about 5.50 hour

welshfella · Answer

inverse variation  :-
t = k/r   where k is a constant

welshfella · Answer

4 hours at 40 mph
so 
4 = k/40
solve this for k

welshfella · Answer

replace k in the equation by the value  for k you just found
this will give you the relation between t and r

To find t when r = 55

plug in r = 55 and calculate t

welshfella · Answer

can you solve 4 = k/40 ?