$15 because a mean would allow him to spend $250 over the five months BUT he has already spent $235.
$250 - $235 = $15
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.
Answer:
y = 9x
Step-by-step explanation:
You can set up linear equations like this: y = mx + b, where m is the slope or rate, and b is the y-intercept.
9 would be the slope, since he has to pay $9 per gift.
The y-intercept is when x = 0, but if he doesn't buy any gifts, he won't have to pay anything, so b = 0. You don't have to include it since it's 0.
So, it's just y = 9x
Hope that helps! :D
The answer is : It is more than the number of student who prefer movies and picnics combined.
!!HOPE THIS HELPS!!