Probability related Questions by Balaji

[Balaji]

consider the 4 digit no abcd what is the probability that sum of the digits is greater than or equal to 4 ?



a) 899/900



b) 1/900



c) 299/300



d) 599/600

answer choice d



solution



case 1 sum of digits =1



case 2 sum of digits =2



case 3 sum of digits  =3



probability (sum of digits > or equal to 4) = 1-1/600

=599/600


 

[Balaji]

Ram selects 2 two digit no at random and mutiple them what is the chance that the product will end in zero



a) 1/3



b) 27/100



c) 28/81



d) 29/100

answer choice b



solution



overall probability = (1539+648)/90*90

=2187/8100

=27/100