A bag contains 10 blue objects and 10 red objects. There are 5 blue circles, 5 red circles, 5 blue squares and 5 red squares. If two objects are drawn from the bag without replacement, what is the probability of getting both a red and blue object?
A)
1
10
B)
1
4
5
19
D)
9
38

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.