Prog2.4 -- adding floats give wrong answer?

[rue]

Based on Progr 2.4, I tried using float numbers.

Code: (Objective-C)

float sum;
        
        sum = 50.5 + 25.12;
        NSLog(@"The sum of 50.5 and 25.12 is %f",sum);

But Xcode says the answer is:
The sum of 50.5 and 25.12 is 75.620003

What gives?
Where did the 0.000003 extra value came from?

[rue]

Okay, found the answer to my question.

This one works. i.e. using double instead of float.
The question is why?

Code: (Objective-C)

   double sum;
        
        sum = 50.5 + 25.12;
        NSLog(@"The sum of 50.5 and 25.12 is %f",sum);

 The sum of 50.5 and 25.12 is 75.620000