Answer:
20 feet
Step-by-step explanation:
There are 3 feet in a yard, so 9 yards and 1 foot = 28 feet. You find this by multiplying 9x3 = 27 and adding the extra foot, which makes it 28. To find the final answer just subtract 8 from 28, which gives you 20.
5a - 4a = -9 - 8a
a = -9 - 8a
9a = -9
a = -1
Answer:
D. 2/7
Step-by-step explanation:
The probability is calculate as a division between the number of ways in which Andrew will be selected and karen will not and the total ways in which they can select 4 people from a group of 8 volunteers.
The number of ways in which they can select 4 people from a group of 8 volunteers can be calculated using:

Where nCk give as the number of ways in which we can form groups of k elements from a group of n elements.
So, if we replace n by 8 and k by 4, we get:

Then, there are 70 ways to select 4 people from a group of 8 volunteers.
At the same way, the number of ways in which Andrew will be selected and karen will not can be calculate replacing n by 6 and k by 3 in the same equation as:

We replace n by 6 because from the 8 volunteers, Andrew is going to be selected and Karen will not, so, the people that affect the result are just the 6 remaining volunteers. Also, k is equal to 3 because Andrew is already selected and we just need to select 3 more people.
Finally, the probability is:

I think the answer is C. 45 units