Hello, Here is a link to the answer. I am posting this link because it is a Brainly link and a verified answer
brainly.com/question/219158
You want to end up with
. Expand this using the angle sum identity for sine:

We want this to line up with
. Right away, we know
.
We also need to have

Recall that
for all
; this means

Then

So we end up with

Answer:
3
Step-by-step explanation:
Considering she wore a black shirt 6 times in 20 days will give you the statistic of 3/10. If the question is about the next 10 days then she will wear 3 black shirts. (It's also 1/2 of the original question.)
P = paddling speed
C = speed of the current
Upstream: 6 = 4 (P - C. Downstream: 6 = 3 (P + C)
4P - 4C = 6
3P + 3C = 6
12P - 12C = 18
12P + 12C = 24
Add the equations:
24P = 42. P = 42/24 = 1.75 mph
Subtract the equations:
-24C = -6
C = 0.25 mph