Question

Question no.6,7,8
[probability class 10]

Answer 1

you have to select more points :-)
=====================
6) a)
coins :

1)HHH

2)THH

3)HTH

4)TTT

5)THT

6)HTT

7)HHT

8)TTH

¡)P(e) of all head =1/8

¡¡) p(e) of exactly two head=3/8

¡¡¡)p(e) of all tails=1/8

¡v)p(e) of atleast one head=7/8

v)p(e) of exactly one head=3/8

v¡)p(e) of atleast two head=4/8=>2/4

======================

b)
now, total cards are 51
so,

i) p(e) of getting heart =13/51

¡¡)p(e) of getting a king =3/51=>1/17

¡¡¡)p(e) of getting a club =12/51

¡v)p(e) of getting the 9 of spade=9/51
>>>>>>>>>(★)<<<<<<<<<<<
7)
a)

i) total multiples of 3 or 5 between 1 to 30:

3,5,6,9,10,12,15,18,20,21,24,25,27,30.

total=14

p(e) =14/30=>7/15

¡¡)

p(e) of getting a multiple of 3 and 5=16/30=>8/15

¡¡¡) total multiples of 4 or 6 :

4,6,8,12,16,18,20,24,28 ,30

p(e)=10/30=>1/3
===============

b)

i) 2,4,6,8...100

let the no. of even no. be n

tn=>a+(n-1)d=100

=>2+(n-1)2=100

=>(n-1)=98/2

=>n=49+1

=>n=50

probability=50/99

=50/100=>1/2

¡¡) perfect square:

4 ,9,16,25,36,49,64,81,100

p(e)=9/100

iii) p(e)=13/100

¡v)

2,3,5,7,11,13,17,19,23, 29

p(e)=10/100=>1/10

>>>>>>>>>(★)<<<<<<<<<<

8)

a)

p(e)=10/40=1/4
===============
b)

let the number of blue balls in the bag be x .

then ,total number of balls=(5+x).

given: p(a blue ball)=2×p(red ball)

•°• x/(5+x)=2×{(5)/(5+x)}

=>x=10

hence ,the number of blue balls in the bag is 10

>>>>>>>>(★)<<<<<<<<<