To find out how many donuts Kristen bought, you can multiply the number of boxes by the number of donuts in each box.
Kristen bought 2 boxes of donuts, and each box contains 8 donuts:
\[ 2 \text{ boxes} \times 8 \text{ donuts/box} = 16 \text{ donuts} \]
So, Kristen bought 16 donuts.