The grocer prepared total 110 samples.
Step-by-step explanation
Suppose, the total number of samples the grocer prepared is

By lunchtime, the grocer has given out 5 fewer than half the total number of samples. So, the number of samples given out by lunchtime

Now, it is given that she gives out 50 samples before lunch. That means...

So, the total number of samples the grocer prepared is 110.