something times 2 plus itself equals 36.
2 times 12 = 24
24 plus 12 = 36
2 x 12 +12 =36
or
36 divided by 3
or
12x = 36
by dividing 12 into 36, x =3
Because 36 is a whole and even number, Kim's sister's age should be even as well. The age would be multiply itself 3 times. So Kim's sister is 12 yr old, and Kim's age is 24 years old.