If I double my number then it is equal to the number I though of yesterday he also says the number i thought of yesterday was 4 less than 3 times today's number what number did the magician think of yesterday

Solution

I f I d o u b l e m y n u mb er t h e n i t i s e q u a l t o t h e n u mb er I t h o ug h o f yes t er d a y h e a l so s a ys t h e n u mb er i t h o ug h t o f yes t er d a y w a s 4 l ess t han 3 t im es t o d a y^{'} s n u mb er w ha t n u mb er d i d t h e ma g i c ian t hink o f yes t er d a y

The number : - 2 or 0

Solution steps

Represent the number with

x

A.T.Q.:

2 x = 3 xx - xx \cdot 4

Solve for

x, 2 x = 3 xx - xx \cdot 4 : x = - 2, x = 0

The number : - 2 or 0