Could you show me the work. on how to get the answer of 15.20

Will give brainliest series to sigma notation write the following series in sigma notation. 6+10+14+18+22+26+30 example image shown below.

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

Arectangular courtyard is 12 feet long and 8 feet wide. a tile is 2 feet long and 2 feet wide. how many tiles are needed to cover the courtyard?