Math Problem

Where did the money go?

There were three friends having dinner together, when the waiter brought their bill, which was $30. Each paid $10.
After collecting the money the waiter realized that t he bill should have been $26 insted, dua to a special discount.
Unsure on how to divide $4 equally among three people, he put $1 in his pocket ang gave each person $1. This means that each person paid $9 for their dinner.
It happens that 9 x 3 + 1 = 28. What happened to the other $2?

actually it would be 50 mph.  If you think of an hour as 60 minutes, then 40mph become 4/6 mpm, 60 mph become 1 or 6/6 mpm, and 50 mph becomes 5/6 mpm, so we say(4/6+6/6+x/6)/3 (since it is an average of three speeds)=5/6 (50 mph).  Multiply 5/6 by three and get 15/6=(4/6+6/6+x/6), simplify...15/6=(10/6+x/6), subtract 10/6 from both sides and you get x/6=5/6 otherwise known as 50 mph