Answer: d. 9 mi/h downstream, 6 mi/h upstream
Explanation:
Hi, the correct answer is option d.d. 9 mi/h downstream, 6 mi/h upstream.
We have to analyze the information given:
"She rows downstream 3 miles/hour faster than she rows upstream."
So, with this information we have to choose the option that has the difference of 3 miles perhour between the downstream speed and the upstream speed.
9mi/h-6mi/h = 3mi/h
Or, we can calculate it :
x= upstream rowing rate
6/ (x+3) = 4/x
6x = 4 (x+3)
6x =4x+12
6x-4x= 12
2x =12
x=12/2
- x=6mi/h =upstream rowing rate.
by adding 3mi/h, we obtain the downstream rowing rate:
- 6mi/h + 3mi/h = 9mi/h downstream rowing rate.