Half of a two-digit number is greater than 10 times its unit digit by 1 more than the ten's digit of that number. If the sum of the digits present in the number is equal to 7, then what is the number?
52
Let the ten's digit be x and unit's be y. Then,
10x+y2−10y=(x+1)
⇒10x+y=20y+2x+2
⇒8x−19y=2....(i)
and x+y=7....(ii)
Solving (i) and (ii), we get: x = 5 and y = 2. Hence, required number = 52.