In a school, students using school bus, bike and bicycle for transport are in the proportion 6 : 3 : 1. If the total strength of the school is 1200, find the number of students who use bicycle for transport. (Each student uses only one of the given 3 modes of transport)

120

                              Bus  :  Bike  :  Bicycle 

No. of students          6   :     3    :      1

Total = 10r =1200 

               r = 120

No. of students using bicycles = r = 120

Alternate method, 

No. of students using bicycle as mode of transport = $\frac{1}{10}$ x Total no. of students = $\frac{1}{10}$ x 1200 = 120