Given that a bike shop rents bikes with heights ranging from 18 inches to 26 inches. And the height of the bike should be about 6 times a cyclist legs length.
Let x be the cyclist leg length.
From given condition If 0.6x is between 18inches to 26 inches, then only cyclist can rent bike.
Then condition for cyclist not getting bike is 0.6x<18 or 0.6x>26
x<
or 
x<30 inches or x>43.33 inches
5 + 0.50p = 6.50
0.50p = 6.50 - 5
0.50p = 1.50
p = 1.50/0.50
p = 3 <=== the vehicle had 3 people in the vehicle