I'm trying to do this problem, but i have no idea how to even start it:

shirts. com advertises a limited time sale, offering 1 turtleneck sweater for $15 and 2 turtleneck sweaters for $25. a total of 1250 turtlenecks are sold and $16,750 is taken in. how many customers ordered 2?

65 8 7 4 5 6 8 4 3 2 1 9 5 6 4 2 1 6 5 1 5 1 3 2 3 5 multiply the third number in the first row by the seventh number in the third row. add this result to the fifth number in the second row. add to this total ten times the fourth number in the third row. subtract the eighth number in the first row from the result.

Abox contains 1 plain pencil and 4 pens. a second box contains 5 color pencils and 5 crayons. one item from each box is chosen at random. what is the probability that a plain pencil from the first box and a color pencil from the second box are selected? write your answer as a fraction in simplest form.

Find the midpoint m of z1=(8+5i) and z2=(12+3i)