Question

How many three-digit numbers greater than 200 can be formed from the digits 1, 2, 6, 7, and 9, if the digits can be repeated?

Answer 1

Answer choices are
64
100
125

Answer 2

@ShadowLegendX

Answer 3

digits can be repeated

_ _ _

we're looking a 3 digit number

the first digit has to be 2 or greater

we only have 2, 6, 7, or 9
the other two spots can be 1, 2, 6, 7, or 9

Answer 4

I know it goes

n!
----
(n-r)!r!

I just dont know how to substitute

Answer 5

for this one, we can use the counting princple

what are the # of possible numbers that could go in the first digit? in the 2nd digit? 3rd digit?

and you multiply it

Answer 6

not sure how to use that formula here... it's easier to use the counting princple :P

Answer 7

oh so that would be

100

Answer 8

because 5^3

Answer 9

5^3 = 125

but the first digit can only have 4

because if use 1 in the first digit the number will be less than 200

so 4 * 5 * 5

Answer 10

oh okay that makes sense thank you so much!

Answer 11

but 4 * 5 = 20 and 20 * 5 = 100?

Answer 12

OH I SEE LUL MY BAD

Answer 13

I got the correct answer by doing basic math incorrectly sorry

Answer 14

yeah :)