50 would be a good choice of answer
Answer:
Step-by-step explanation:
The straight line equation is:
y = m*x + b Where m is the slope of the line and b the intercept with y-axis, in our case y is the depth of the tank and x (time in lapsus of 3 hours).
The slope m = ( y₂ - y₁ ) / (x₂ - x₁)
We have point A ( 3 , 8 ) and point B ( 6 , 7 )
m = ( 6 - 3 ) / (7 - 8 ) m = -3
We see that each 3 hours time-depth decreases 1 in.
Then to find the depth at the beginning of x-axis
At noon 12 tank was 9 inches, three hours before at 9 in the morning the depth was 10 inches and:
9 in the morning 10
6 in the morning 11
3 in the midnight 12
12 in the night 13
Then 13 is the intercept with y-axis
then the equation is:
h = - 3*x + 13
Note x is time in lapsus of 3 hours
To do this we take the outlier off the parenthesis (the 4) and multiply it by the two numbers inside the parenthesis...
4*7 + 4*8
28+32
Answer:
y = - 10
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 2 when x = - 4, that is
2 = - 4k ( divide both sides by - 4 )
= k, that is
k = -
y = - x ← equation of variation
When x = 20, then
y = - × 20 = - 10
