Big Brain Math

What is 23 raised to the power of 23?

If x and y are the tens digit and the units digit, respectively, of the product 725,278 * 67,066, what is the value of x + y.

Five times the sum of a number and twelve is 70

A man took a trip in a car. He drove 70 miles at a slower speed. Then, he went the next 300 miles at a speed that was 40 mph faster than earlier. The time he spent driving at the faster speed was twice the time spent at the slower speed. Find the two speeds.