Question

The sum of the digits of a positive two-digit number is 13,If twice the first digit is 1 less than the second digit,what is the two-digit number ?

Answer 1

49, 58, 67, 76, 85, or 94

Answer 2

Let t = ten's digit
Let x = one's digit

t + x = 13

2t= x-1 or 2t+1 = x

You can substitue for "x"

t + 2t + 1 = 13
3t = 12
t = 4 find x = 9

so we have 49