Answer: Python Puzzler #1780

The answer is D. The program prints:

10 0
What the program prints
Checked by running the program for real.

Why?

// divides and throws away the remainder: each friend gets 10 sweets. % gives the remainder: 0 sweets left over.

Trace table

A trace table follows the program step by step. Here’s this one:

sumanswer
20 // 210
20 % 20

The code again

sweets = 20
friends = 2
print(sweets // friends, sweets % friends)

Try it: change one number in the program and predict the new output before you run it.