deepak
Last Activity: 8 Years ago
if x2+bx+c>0
then it implies that discriminant should be less than zero
i.e. b2-4c>0
hence b>2

if c=1 then b can be 3,4,5,6,7,8,9 …..7
if c=2 then b can be 3,4,5,6,7,8,9 …....7
if c=3 then b can be 4,5,6,7,8,9 ........6
if c=4 then b can be 5,6,7,8,9 …........5
if c=5 then b can be 5,6,7,8,9 …........5
if c=6 then b can be 5,6,7,8,9 ….…...5
if c=7 then b can be 6,7,8,9 ….….4
if c=8 then b can be 6,7,8,9..........4
if c=9 then b can be 7,8,9 ….3
therefore total no of favourable pairs are 46
then the probability of the given even happening is 46/81 = 0.567
hope it is useful