A boat takes 4 hours to go 20 miles upstream. It can go 32 miles downstream in the same time. Find the rate of the current and t
he rate of the boat in still water. (Hint: Because the current pushes the boat when it is going downstream, the rate of the boat downstream is the sum of the rate of the boat and the rate of the current. The current slows down the boat when it is going upstream, so the rate of the boat upstream is the difference of the rate of the boat and the rate of the current.)
Let the boat speed in still water be b. Let the current speed be c. The speed going upstream is 20/4 = 5 mph. The speed going downstream is 32/4 = 8 mph. b - c = 5 ........(1) b + c = 8 .......(2) Adding equations (1) and (2) we get: 2b = 13 b = 13/2 = 6.5 Plugging in the value for b into equation (1) we find c = 1.5. The boat speed in still water is 6.5 mph and the current speed is 1.5 mph.
One possible difference is that a straight angle is just a single angle measuring 180 degrees, while a linear pair supplementary angle are pairs of adjacent angles that add up to 180 degrees.
<u>The probability that the marble will be blue if he shakes the bag and when you puts his hand into the bag, to move it around and probably he'll get the blue marble.</u>
