Ashirt originally cost $36.24, but it is on sale for $30.80. what is the percentage decrease of the price of the shirt? if necessary, round to the nearest percent.
85%
18%
12%
15%
the last few question i had no one has like why?

To work out the decrease, do original amount - new amount and then take that answer and divide it by the original amount, and then multiply by 100.

So you would do:

36.24 - 30.80 = 5.44
5.44 ÷ 36.24 × 100 = 15% to the nearest percent.  

She should use 12/3 to measure

1/b^3m^3               i don't know why you couldn't do it yourself its not that hard