As y varies directly with x, there is a proportionality constant. As x increases by that certain constant, y also increases. We equate:
y = kx
where k = proportionality constant.
Given the condition, y = 5 when x = 4, then we solve for k:
5 = k(4)
k = 5/4 or 1.25
When y = 8, then
8 = (5/4)(x)
x = 8/(5/4) = (8)(4/5) = 32/5 or 6.4 (ANSWER)
Answer:
D
Step-by-step explanation:
-1 + -5 is -6.
Answer:
Depth of the rain gutter is 8 inches
Step-by-step explanation:
Let’s assume ‘x’ is the depth of the rain gutter
Then the width of the rain gutter can be written as 16 - 2x
Cross sectional area
A = depth x width
Substitute values
A = x*(16 - 2x)
A = 16x – 2x^2
Now according to axis of symmetry for maximum area x = -b/2a
x = -16/2*(-2)
x = 4 inches depth of rain gutter, substitute the value of x to get
Width of rain gutter 16 – 2(4) = 8 inches
Area of the rain gutter for maximum water flow
A = 4 * 8
A = 32 square inch.
So,
0.2(n - 6) = 2.8
Distribute.
0.2n - 1.2 = 2.8
Add 1.2 to both sides.
0.2n = 4
Divide both sides by .2.
n = 20
Check.
0.2(20 - 6) = 2.8
Simplify inside parentheses.
0.2(14) = 2.8
Multiply.
2.8 = 2.8 This checks.
S = {2.8}
