What is the mean of the data set?

12, 17, 16, 10, 20, 13, 14, 14, 12, 12, 19, 18

a.14.00

b.14.75

c.13.50

d.15.75

The sum of the product of 4 and x and the product of 7 and y is 61. the sum of the product of 12 and x and the product of 21 and y is 61. what are the values of x and y?

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?