We can use ratios to compare these numbers.
60 pistachios:3 discarded
380 pistachios: ? discarded
60 x 6 1/3=380 total
3 x 6 1/3=19 discarded
19 of the 380 pistachios should be discarded. Another way to figure out the solution is by calculating the percentage of discarded pistachios then applying it (60/3 = 5% discarded).