Use the chart of quiz scores to find the weighted mean

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

Your company will replace the asphalt roofs on all the buildings at the factory complex shown below. the buildings have flat roofs. you charge according to the total roof area. what is this area, in square yards?

In . -15, -7, 1, a)7,13,19,21 b) 10,19,28,37 c)9,17,25,33 d)7,15,25,37