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Problems
Contests
National and Regional Contests
PEN Problems
PEN A Problems
66
66
Part of
PEN A Problems
Problems
(1)
A 66
Source:
5/25/2007
(Four Number Theorem) Let
a
,
b
,
c
,
a, b, c,
a
,
b
,
c
,
and
d
d
d
be positive integers such that
a
b
=
c
d
ab=cd
ab
=
c
d
. Show that there exists positive integers
p
,
q
,
r
,
s
p, q, r,s
p
,
q
,
r
,
s
such that
a
=
p
q
,
b
=
r
s
,
c
=
p
s
,
d
=
q
r
.
a=pq, \;\; b=rs, \;\; c=ps, \;\; d=qr.
a
=
pq
,
b
=
rs
,
c
=
p
s
,
d
=
q
r
.
Divisibility Theory