Noah spent $20 of food.
To find this, we have to find out the cost for everything individually. Onions are $2 per pound, and he bought 5 pounds. So we would do 5*2, which equals $10. The bag of salad greens is $4, so the total there is $4. Cereal is $3 per box, and he bought 2. We would do 3*2 = $6. Finally we add together everything to get the total ($10 + $4 + $6 = $20)
I hope this helps!
