Math Riddles

Question: Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation.

Note: Each must be used exactly once and no other numbers or symbols can be used.

Question: If you have an 11 minute and 13 minute hourglass, how can you accurately time 15 minutes?

Question: There are two planes. One is going from New York to London at a speed of 600 MPH. The other is traveling from London to New York at a speed of 500 MPH.

When the planes meet which one will be closer to London?

Question: If 1+9+8=1, what is 2+8+9?

Question: A hobo picks up cigarette butts from the ground and can make a cigarette with 4 butts. If he finds 16 cigarette butts, how many cigarettes can he make?