# TSI Math: How Many Times Will Jaqen Roll Two 10s?

Jaqen has two 10-sided dice. He rolls both at the same time. What is the probability that both faces add up to a number less than 20?

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### Transcript

00:24

combination of faces adds up to a number less than

00:27

twenty much faster to find the probability of rolling two

00:29

tens and find the probability of all the other possible

00:32

roles so just take the shortcut there Well the probability

00:34

of rolling ten on one dies one in ten because

00:37

each of the ten faces has an equal probability of

00:40

turning up The probability of rolling to tens then is

00:43

one over ten times one over ten or one over

00:47

one hundred or one percent The probability of rolling anything

00:50

other than two tens and a rowing to faces that

00:53

add up to a number less than twenty is one

00:55

minus the probability of that one hundred shot So it's

00:59

ninety nine out of one hundred probability that both faces

01:02

add up to a number less than twenty is ninety

01:05

nine out of one hundred And yeah we like those

01:07

odds So the answer is c and we're so shmoop