Sumo 4. A train moving with the speed of 30 km per hour travelled from Kamalapur station to Narayangonj station. If the speed of the train was 25 km per hour, it would take 10 minutes more for the journey. What is the distance between the two stations ?

9 x 8 divided by (5-3)=36

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

c) yes, because of asa or aas