Giving away points for free

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

List x1, x2, x3, x4 where xi is the left endpoint of the four equal intervals used to estimate the area under the curve of f(x) between x = 4 and x = 6. a 4, 4.5, 5, 5.5 b 4.5, 5, 5.5, 6 c 4.25, 4.75, 5.25, 5.75 d 4, 4.2, 5.4, 6

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).