Answer:
(c)
Step-by-step explanation:
Using the cosine ratio in the right triangle
cos42° = 
= 
Multiply both sides by 12
12 × cos42° = x, hence
x ≈ 8.9 → (c)
The answers are:
P(9, 2) = 72
P(5, 5) = 120
P(7, 7) = 5040
These are examples of permutations. The problems are asking us to find the total number of ways an event can happen.
In the first case, P(9, 2), we are asked to find the ways that 2 things can be chosen out of a group of 9.
9 x 8 = 72
P(5, 5) = 5 x 4 x 3 x 2 x 1
P(7, 7) = 7 x 6 x 5 x 4 x 3 x 2 x 1
The answer is 7 because it goes 10th 100th and the thirty one is thousands
Answer: at 50 mph, she drove for 4 hours.
at 45 mph, she drove for 2 hours.
Step-by-step explanation:
Let t represent the time that she spent driving at 50 miles per hour.
Taylor took 6 hours to drive home from college for Thanksgiving break. This means that the time that she spent driving at 45 miles per hour is (6 - t) hours.
Distance = speed × time
Distance covered while driving 50 miles per hour is
50t
Distance covered while driving 45 miles per hour is
45(6 - t)
Since the total distance that she drove is 290 miles, it means that
50t + 45(6 - t) = 290
50t + 270 - 45t = 290
50t - 45t = 290 - 270
5t = 20
t = 20/5 = 4
At 45 miles per hour, she drove at
6 - 4 = 2 hours
