Daily Puzzle Fifty Two Answer

26

Let Holly’s number be x, then x² – 20x = 156

Rearrange this to x² – 20x – 156 = 0 and solve by factorising

(x + 6)(x – 26) = 0 so x = -6 or  x = 26, but since Holly is thinking of a positive integer, her number must be 26.