Question

cards with 1,2,3,... 100 are placedin a box and mixed thoroughly if one card is drawn what is the probablity that card drawn is :
1) a prime number less than 30
2) a multiple of 5 or 6
3 ) a multiple of 5 and 7

Answer 1

Possible outcomes =100
1) 2,3,5,7,11,13,17,19,23,29
Favourable outcomes =10
P(a prime no. less than 30)=10/100=1/10

2)5,6,10,12,15,18,20,24,25,30,35,36,40,42,45,48,50,54,55,60,65,66,70,72,75,78,80,84,85,90,95,96,100
favourable outcomes =33
P(multiple of 5 or 6)=33/100

3)5,7,10,14,15,20,21,25,28,30,35,40,42,45,49,50,55,56,60,63,65,70,75,77,80,84,85,90,91,95,98,100
favourable outcomes =32
P(a multiple of 5 or 7)=32/100=8/25