Question

Lisa has 3 cards numbered 6, 8, 10 and Keari has 3 cards numbered 1, 9, 9. If each of them select a card at random, what is the probability that the sum of the two cards will be less than or equal to 17?

Answer 1

Probability that the sum of the two cards will be less than or equal to 17 is
`(5)/(6)`

Explanation:

Let the probability of an event be denoted by 'P'.

We know that the probability of an event is defined as:

`Probability=(Number of favourable outcomes)/(Total number of outcomes)`

The total number of outcomes of choosing a card is:

(6,1) (6,9) (8,1) (8,9) (10,1) (10,9)

Where the first entry denote a card number chosen by Lisa and second entry denote a card number chosen by Keari.

the sum of these entries is: (6,1)=6+1=7

(6,9)=6+9=15

(8,1)=9

(8,9)=17

(10,1)=11

(10,9)=19

The total number of outcomes=6

the number of outcomes such that the sum of the two cards will be less than or equal to 17(number of favourable outcomes)=5 { (6,1),(6,9),(8,1),(8,9),(10,1)}

P(sum of the two cards will be less than or equal to 17)=
`(5)/(6)`.