1)Out of 2n+1 cards numbered successively, 3 cards are drawn. What is the probability tat the numbers on the card are in A.P?
Ans:3n/4n2-1
2) Each question in the eq ax2+ bx+c is obtained by tossing a Die. Find the probability tat the equation will show real roots?
Ans:43/216
242) b2-4ac≥0
for b=1 a=c=0 satisfy
for b=2 a=c=1
forb=3 (1,1),(1,2),(2,1)
for b=4 (1,1)....(1,4)
(2,1),(2,2)
(3,1) ,(4,1)
for b=5 (1,1).....(1,6)
(2,1).,....(2,3)
(3,1)(3,2)(4,1)(5,1)(6,1)
for b=6 (1,1)......(1,6)
(2,1)...(2,4)
(3,1)...(3,3)
(4,1)(4,2)(5,1)(6,1)
=>favourable=43
P=43/216
any other shorter method is welocme
1i agree good questions,i think the first one was a JEE question,had seen it some time before
24Sir Q2 ke liye koi aur method hai kya????????kyunki isme 2 minute lag gaye.......[2]
