Let 1/2 of the no. = 10x + y
and the no. = 10v + w
From the given conditions,
w= x and v = y-1
Thus the no. = 10 (y-1) + x
∴ 2(10x + y ) = 10 (y-1) + x
⇒ 8y - 19x = 10 ...(i)
v + w = 7
⇒ y-1 + x = 7
∴ x + y = 8
Solving equations (i) and (ii) , we get
x = 2 and y = 6
∴ From equations (A)
Number = 10 (y - 1) + x = 52.