13

13 — Practice solutions

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These are independently written explanations, not an official marking scheme.

13A

Results: 3 int; 2 int; -3 int; 2 int; "444" str; 14 int. Floor division rounds the quotient downward, including for negative values.

Reasoning

Do not use truncation for the negative quotient: floor means round downward. Check remainder through a = quotient × divisor + remainder. String repetition concatenates copies rather than multiplying a numeric value; multiplication precedes addition in the final expression.

13B

def boxes_needed(items, capacity):
    boxes = items // capacity
    if items % capacity != 0:  # Only a partial final box adds another box.
        boxes += 1
    return boxes

The expected results are 0, 2, 3. Adding one unconditionally fails for exact multiples and for zero items.

Reasoning

Integer division counts completely filled boxes; a nonzero remainder needs one additional box. The given nonnegative/positive input conditions make this decomposition valid. Do not add an extra box when items is 0 or an exact multiple.