The half life of a certain substance is about 4 hours. The graph shows the decay of a 50 gram sample of the substance that is measured every hour for 9 hours. Which equation can be used to determine the approximate number of grams of the sample remaining after t hours?

A. y = 50(1/2)^t/4
B. y = 50(1/2)^t/9
C. y = 25(1/2)^t/4
D. y = 25(1/2)^t/9

Please explain!

Lin is shopping for a couch with her dad and heard him ask the salesperson “how much is your commission? ” the salesperson says that her commission is 5 1/2% of the selling price. a.how much commission will the salesperson earn by selling a couch for $495? b.how much money will the store get from the sale of the couch?

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Adam plans to choose a video game from the section of the store where everything is 75% off. he writes the expression d-0.75d to find the sale price of the game if the original price is d dollars. gena correctly writes another expression, 0.25d, that will also find the sale price of the game if the original price is d dollars. use the drop down menus to explain each part of adams and rena's expression