a two digit no is such that the product of its digits is 18.When 63 is subtracted from the no ,the digits interchange theirplaces .Find the no.

Asked by snisarulhaq | 28th Dec, 2017, 02:02: PM

Expert Answer:

begin mathsize 16px style Let space the space two space digit space number space be space 10 straight u plus straight v.
uv equals 18.......... left parenthesis 1 right parenthesis
10 straight u plus straight v minus 63 equals 10 straight v plus straight u
9 straight u minus 9 straight v equals 63
straight u minus straight v equals 7......... left parenthesis 2 right parenthesis
From space left parenthesis 1 right parenthesis
straight u equals 18 over straight v
straight u minus straight v equals 7
18 over straight v minus straight v equals 7
18 minus straight v squared equals 7 straight v
straight v squared plus 7 straight v minus 18 equals 0
Solving space you space get space straight v equals negative 9 space or space 2
As space digit space is space always space positive space straight v equals 2
straight u minus straight v equals 7
straight u minus 2 equals 8
straight u equals 9
Hence comma space the space number space is space 92.

end style

Answered by Sneha shidid | 28th Dec, 2017, 02:16: PM