In a two-digit number, the tens digit is twice the ones digit. The difference of the ones digit and half the tens digit is 0. find an equation to find the digit in the ones place

Question

will the question have one solution no solution or many solutions

Answer 1

t=2u

u-t/2=0

u-2u/2=0

u-u=0

4 solutions

21

42

63

84

unit digit =1,2,3 or 4

4 is "many"

tempting to say infinite solutions, which would be true, except for the restriction that the solution has be an integer. That narrows it down to four possible solutions