Question

Three dice are rolled once. What is the chance that the sum of the face numbers on the dice is (i) exactly 18 (ii) exactly 17 (iii) atmost 17.

Answer 1

(I)....... Answer..... .

Answer 2

Hi ,

If three dice rolled once ,then

number of total possible

outcomes = 6³ = 216 ---( 1 )

i ) getting exactly 18

Favorable outcomes = { ( 6,6,6 ) }

Number of favourable

outcomes = 1 -----( 2 )

P( getting 18 ) = ( 2 )/( 1 )

= 1/216

ii ) getting exactly 17

Favorable outcomes = { (6,6,5 ) ,

( 6, 5 , 6 ) , ( 5 , 6 , 6 ) }

Number of favourable

outcomes = 3 -----( 3 )

P( getting exactly 17 ) = ( 3 )/( 1 )

= 3/216

= 1/72

iii ) getting at most 17 ,

Number of favourable

outcomes = 215 ---( 4 )

P( at most 17 ) = ( 4 )/( 1 )

= 215/216

I hope this helps you.

: )