a two digit number is such that the product of digits is 20 if 9 is subtracted from the number then the digits are reversed find the number
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LET NO AT UNIT PLACE BE N AND AT TES BE M
EQUATION 1 IS
MN=20
10M+N-9=10N+M
9M-9N=9
M-N=1
M=1+N
SUBSTITUTING VALUE IN MN=20
(N+1) N=20
N^2+N-20=0
(N-4)(N+5)=0
N=4 N CANNOT BE - 5
M=1+N
M=5
NUMBER IS 54
54-9=45
CONDITION SATISFIED
EQUATION 1 IS
MN=20
10M+N-9=10N+M
9M-9N=9
M-N=1
M=1+N
SUBSTITUTING VALUE IN MN=20
(N+1) N=20
N^2+N-20=0
(N-4)(N+5)=0
N=4 N CANNOT BE - 5
M=1+N
M=5
NUMBER IS 54
54-9=45
CONDITION SATISFIED
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