Sharon paid $78 on sales tax. The sales tax rate is 6.5%, what was the cost of the camera? Please help, I've been trying for an hour now my assignment is past due.

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.