Math Problems

If this day doesn't come after Monday or before Thursday, and tomorrow isn't Sunday and yesterday wasn't Sunday, and the day after tomorrow isn't Saturday and the day before yesterday wasn't Wednesday, then what day is it?

There are 800 women in a certain African village. Three percent of them wear one earring each; half of the women—who make up the remaining 97 percent—wear two earrings each; and the other half do not wear any earrings at all. How many earrings are there in total among the village’s female population? Solve this problem mentally, without using any calculators or other aids.

A car would pick up a certain manager, who lived at his country house, every morning and take him to work by a specific time. One day, the manager decided to take a walk; he left an hour before the car was due to arrive and walked toward it. On the way, he met the car and arrived at work 20 minutes before his shift began. How many minutes did the walk last?

Two passenger trains, each 250 m long, are traveling toward each other at the same speed of 45 km/h. How many seconds will pass between the time the train operators meet and the time the conductors of the last cars meet?