Question

A 100 rupees note was changed into 10 rupees notes and 20 rupees notes.there were 7 notes in all how many of each notes were there.what is the equation of this question?

Answer 1

i did it without any equation. we need the sum 100.
so 100=20*3+10*4. that is it.
so there were 3 twenty rupee notes and 4 ten rupee notes

Answer 2

yes it can be: 100=20*3+10*4