MathDB
Problems
Contests
National and Regional Contests
India Contests
India Pre-Regional Mathematical Olympiad
2018 India PRMO
3
3
Part of
2018 India PRMO
Problems
(1)
2018 preRMO p3 - 6-digit numbers of the form abccba , b odd, divisible by 7
Source:
8/7/2019
Consider all
6
6
6
-digit numbers of the form
a
b
c
c
b
a
abccba
ab
cc
ba
where
b
b
b
is odd. Determine the number of all such
6
6
6
-digit numbers that are divisible by
7
7
7
.
number theory
Digits
divisible