Answer:
Step-by-step explanation:
Cross multiply on both sides
= (x + 1) (21) = 15(x + 3)
= 21x + 21 = 15x + 45
Bringing like terms on one side
21x - 15x = 45 - 21
= 6x = 24
x = 24/6 = 4
Option A is the correct answer
The large hose fills 1 pool in 9 hours written as 1/9
The small hose fills 1 pool in 18 hours, written as 1/18
Now you have 1/9 + 1/18 = 1/x ( x is the unknown time for both hoses).
rewrite 1/9 with a common denominator as 1/18:
1/9 = 2/18
Now you have 2/18 + 1/18 = 1/x
Add the left side:
2/18 + 1/18 = 3/18
Now you have 3/18 = 1/x
Cross Multiply:
3x = 18
Divide both sides by 3"
x = 18/3
X = 6
It will take both hoses 6 hours.
You can solve all of these by using the distance formula. I have shared it below.
Answer:
u = 7
Step-by-step explanation:
Using the slope intercept formula:
Substitute our values from the points and the known slope:
Now we multiply both sides by (8 - u) to isolate the x:
(8-u) x 
= -7 (8 - u)
Next we add 56 to both sides:
-7 = -56 + 7u
Finish off by dividing both sides by 7:
7u = 49
u = 7
