They cant be equivalent since neither of them are a equation. they are just plain t=8 or t=10. t cant be both 8 and 10.
4x-10>1000. Hope this helps!:)
8:45
-7:35
1:10 = 70 minutes
You can subtract that way or by knowing that there are 60 minutes in an hour and 8:35 to 8:45 is ten minutes you also get 70.
Don't see any options, but b+c would be traveling with the current, and b-c would be traveling against the current.
200 is not a perfect square because the square root of 200 is 14.14. The cubed root of 200 is 5.85. Because neither answer is a whole number (in both answers, there were more numbers after, but I rounded), I wouldn't classify 200 as a perfect square or a cube.