Check my work Check My Work button is now disabled3Item 7Item 7 10 points An article describes a study in which a new type of ointment was applied to forearms of volunteers to study the rates of absorption into the skin. Eight locations on the forearm were designated for ointment application. The new ointment was applied to four locations, and a control was applied to the other four. How many different choices were there for the four locations to apply the new ointment?

70 combinations

Step-by-step explanation:

Given:

- The total number of designated location n = 8

- The number of location the ointment is to be applied r = 4

Find:

How many different choices were there for the four locations to apply the new ointment?

Solution:

- For this question we will apply combinations to the given problem. We have total of 8 available places out of which we have to "choose" 4 locations to apply the new ointment. We will use combinations " C " operator.

- Out of 8 "choose" 4 = 8_C _4 = 70 possible combinations.

- Since there is requirement of "order" so its only limited to the selection process and not an arrangement.

the answer is 510

step-by-step explanation:

15 • 13 = 195

15 • 12 = 180

15 • 5 = 75

12 • 5 = 60

195 + 180 = 375

375 + 75 = 450

450 + 60 = 510