few algabra questions, need help!

Need help on a few algabra problems.

solve the equation for the indicated variable

1. F=9/5C+32, for C

2. Kevin invested part of his $10,000 bonus in a certificate of a deposit that paid 6% annual simple intrest, and the remmainder in a mutual fun that paid 11% annual simple interest. if his total interst for that year was $900, how much did Kevin invest in the mutual fund?

3. Ken and Kara are 29 miles apart on a calm lake paddling towards each other. Ken paddles at 4 miles per hour while Kara paddles at 7 miles per hour. How long will it take them to meet?

4. A chemist needs 110 mL of a 65% solution but only has 53% and 97% solutions available. Find how many mL of each that should be mixed to get the desired solution.