Can someone help me put this into equations and solve them:

1. Phil has $150 and three-quarters of what Jill has, and Jill has $100 and half of what Phil has, so how much have each?

2. If a teacher can place her students four to a table, there will be three students on the final table. But, if five children are placed on each table, there will be four students on the the last table.

What is the smallest number of children the class could have?

Thanks!