Help with word problems PLEASE!

I have two word problems that do not make any sense please help me.

Here they are:

Sam must have an average of 70 or more in his summer course to obtain a grade of C. His first three test grades were 75, 63, and 68. Write an inequality representing the score that Sam must get on the last test to get a C.

and...

The cost for a long distance phone call is $.36 for the first minute and $.21 for each additional minute or portion thereof. Write an inequality representing the number of minutes a person could talk without exceeding $3.00.