Question

Came across this problem. I think the answer is 89. 1x6y7 is a 5 digit not divisible by 9. The number of ordered pair (x,y) satisfying this is?

Answer 1

i m getting 76

Answer 2

did you count from the complement and subtract from total?

Answer 3

might be wrong

Answer 4

yep

Answer 5

total is 100 right?

Answer 6

wait

Answer 7

yes sry m getting 95

Answer 8

100-5

Answer 9

these are the pairs that I got that makes the number divisible by 9
(0,4), (1,3), (2,2), (3,1) , (4,0)
(4, 9), (5,8), (6,7), (7,6), (8,5), (9,4)

Answer 10

I might under counted

Answer 11

ur answer looks right i didnt count the later x,y pairs

Answer 12

oh ok :)

Answer 13

@souwing @mathmath333
I have the same 11 ordered pairs that @souwing posted.