When you reverse the digits in a two-digit number you increase its value by 18. Find the number if the sum of the digits is 16
ab + 18 = ba where a and b are single digits from 0 to 9
a + b =16 so b = (16-a)
b + 10 a + 8 + 10 = a + 10 b
(16-a) + 10 a + 18 = a + 10(16-a)
9 a + 18 = 9 (16-a)
18 a = 126
a = 7
b = 9