Answer:

Step-by-step explanation:
The systems of equations are
Let us assume the rate of the current be c
Now actual speed against the current is (15 - c)
And, the actual speed with the current is (15 + c)
Here we applied the time formula i.e. distance by speed
Also the upstream time - downstream time = 4
Now the equations are

Answer is c) 2x - 15 because x is Valerie's grade
Allie's grade is <span>taking Valerie's grade, multiply it by 2 and subtract 15</span>
Well think about how many months there’s are!
12 right?
So 12 is the total of months or the denometor
Or bottom number ^^
Now how many months have 31 days?
Figure that out and that your numerator
I'm just eyeballing the chart but imma guess .9
The answer 56 it’s already put in simplest form