I got 6 for my answer, but I'm not 100% sure if I'm right.
6(2x-11)+15=21
12x-66+15=21
12x-51=21
+51 +51
12x=72
----- ----
12 12
x=6
Answer: The answer is (b) The ranger will need to clear trail for more than 10 2/3 additional hours.
Step-by-step explanation: Given that a park ranger would like to clear more than 10 mi of trail. Till now, he has cleared 2 mi. From now on, he can clear 3/4 mi of trail each hour.
Since 2 mi of the trail has already been cleared, so the trail that is left to be cleared = 10 - 2 = 8 mi.
Let, the park ranger will work for 'x' more hours. So, we have

Thus, the park ranger will need to work for 10 2/3 more hours.
Hence, the correct option is (b) The ranger will need to clear trail for more than 10 2/3 additional hours.
Try this solution (see the attachment).
Answer:17.91 calories per minute
Step-by-step explanation:
412 calories burned
23 minutes of riding
412/23 = 17.91 calories per minute
Answer:
Step-by-step explanation:
4) A photograph costs $20, so the cost of x photographs is 20x.
Similarly, the cost of y prints is $25.
So the total cost is 20x+25y, and this has to be less than or equal to 400, so C.
5) just plug each pair in.
For example for the first option, x=5 and y=10, and since 20(5)+25(10)=100+250. which is less than or equal to 400, it works.