a motorboat travels 305km in 5 hours going upstream and 651km in 7 hours going downstream. What is the rate of the boat in still
1 answer:
Recall your d = rt, distance = rate * time.
b = speed rate of the boat.
c = speed rate of the current.
keeping in mind that, as the boat goes Upstream, against the current, it's speed is not "b", but is really " b - c ", because the current is subtracting speed from it.
likewise, when the boat is going Downstream, because is going with the current, is really going faster at " b + c ".
what is the speed of the boat? well, 61 + c = b.
b = speed rate of the boat.
c = speed rate of the current.
keeping in mind that, as the boat goes Upstream, against the current, it's speed is not "b", but is really " b - c ", because the current is subtracting speed from it.
likewise, when the boat is going Downstream, because is going with the current, is really going faster at " b + c ".
what is the speed of the boat? well, 61 + c = b.
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Consider the attached tree.
You start from the root, and with each level you create a sub-branch for each of the choices you have.
So, the root has two children, white and multigrain bread.
Each of those children has three children, because you have three meat choices
Each of those children has two children, because you have two cheese choices.
Then, you identify all the sandwiches by choosing a leaf, and read the label that lead you there.
For example, leaf number 4 represents a sandwich with white bread, turkey and provolone.
The answer is 42.
The question is asking for angle N. We know from the question that angle N is equal to angle E (Don't think about the scale factor because it only applies to the sides. They're just trying to trick you).
To find angle E:
Move numbers to the right side:
Combine like terms:
Divide both sides by 13:
The formula for angle E:
Plug in the 8:
The angle measure of E is 42. So angle N is automatically 42 too.
To solidify, we can try to use the formula which they give us for angle N:
The question is asking for angle N. We know from the question that angle N is equal to angle E (Don't think about the scale factor because it only applies to the sides. They're just trying to trick you).
To find angle E:
Move numbers to the right side:
Combine like terms:
Divide both sides by 13:
The formula for angle E:
Plug in the 8:
The angle measure of E is 42. So angle N is automatically 42 too.
To solidify, we can try to use the formula which they give us for angle N:
First thing to do is to change the radians to degrees so it's easier to determine our angle and where it lies in the coordinate plane. 
. If we sweep out a 210 degree angle, we end up in the third quadrant, with a 30 degree angle. In this quadrant, x and y are both negative, but the hypotenuse, no matter where it is, will never ever be negative. So the side across from the 30 degree reference angle is -1, and the hypotenuse is 2, so the sine of this angle, opposite over hypotenuse, is -1/2