What state is this?
If five cats can catch five mice in five minutes, how long will it take one cat to catch one mouse?
A man has 53 socks in his drawer: 21 identical blue, 15 identical black and 17 identical red. The lights are out and he is completely in the dark. How many socks must he take out to make 100% certain he has at least one pair of black socks?
x² + 5 = 13 - 4