Since we’re trying to find minutes, concert all known information to minutes
1 hr 15 mins = 75 mins
1 hr 30 mins = 90 mins
Next, calculate how many total minutes Gage has skated in the first 8 days
75(5) + 90(3) = 645 mins
Create an equation to find the average of Gage’s minutes of skating. Add up all the minutes and divide by the total amount of days and set equal to 85, the average we are trying to get.
(645 mins + x mins)/9 days = 85
Solve for x
645 + x = 765
x = 120
So, in order to have an average of an 85 minute skate time, Gage would need to skate 120 minutes on the ninth day.
Simplifying
5x + 2(8x + -9) = 3(x + 4) + -5(2x + 7)
Reorder the terms:
5x + 2(-9 + 8x) = 3(x + 4) + -5(2x + 7)
5x + (-9 * 2 + 8x * 2) = 3(x + 4) + -5(2x + 7)
5x + (-18 + 16x) = 3(x + 4) + -5(2x + 7)
Reorder the terms:
-18 + 5x + 16x = 3(x + 4) + -5(2x + 7)
Combine like terms: 5x + 16x = 21x
-18 + 21x = 3(x + 4) + -5(2x + 7)
Reorder the terms:
-18 + 21x = 3(4 + x) + -5(2x + 7)
-18 + 21x = (4 * 3 + x * 3) + -5(2x + 7)
-18 + 21x = (12 + 3x) + -5(2x + 7)
Reorder the terms:
-18 + 21x = 12 + 3x + -5(7 + 2x)
-18 + 21x = 12 + 3x + (7 * -5 + 2x * -5)
-18 + 21x = 12 + 3x + (-35 + -10x)
Reorder the terms:
-18 + 21x = 12 + -35 + 3x + -10x
Combine like terms: 12 + -35 = -23
-18 + 21x = -23 + 3x + -10x
Combine like terms: 3x + -10x = -7x
-18 + 21x = -23 + -7x
Solving
-18 + 21x = -23 + -7x
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '7x' to each side of the equation.
-18 + 21x + 7x = -23 + -7x + 7x
Combine like terms: 21x + 7x = 28x
-18 + 28x = -23 + -7x + 7x
Combine like terms: -7x + 7x = 0
-18 + 28x = -23 + 0
-18 + 28x = -23
Add '18' to each side of the equation.
-18 + 18 + 28x = -23 + 18
Combine like terms: -18 + 18 = 0
0 + 28x = -23 + 18
28x = -23 + 18
Combine like terms: -23 + 18 = -5
28x = -5
Divide each side by '28'.
x = -0.1785714286
Simplifying
x = -0.1785714286
Answer:
rate of the current = 2 mph
Step-by-step explanation:
d = rt
Let c = rate of the current
Rate going downstream = c + 40
Time going downstream = 126/(40 + c)
Rate going up stream = 40 - c
Time going upstream = 114/(40 - c)
Since the times are equal, then
126/(40 + c) = 114/(40 - c)
126(40 - c) = 114(40 + c)
5040 - 126c = 4560 + 114c
240c = 480
c = 2 mph
C is the best answer choice
Chrissy's score = c
Twice means multiply by 2
twice Chrissy score = 2c
the sum of 22 and twice Chrissy score: 22+2c
