Suppose that y varies directly with x and y = 10 when x = 20. What is y when x = 15?
1 answer:
Answer: y = 7.5
Step-by-step explanation:
Suppose that y varies directly with x
That is, y∝x
Convert y∝x to a full equation by introducing a constant k to the right hand side.
Therefore, y = kx
Given that y = 10 and x = 20
Substitute y and x in the equation above. We have;
10 = k(20)
10 = 20k
20k = 10
k = 10/20
k = 0.5
Since k = 0.5, the equation y = kx becomes y = 0.5x
Now, to find y if x = 15, substitute x in equation y = 0.5x
Therefore, y = 0.5(15)
y = 7.5
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Answer:
The number of turbines is 74
Step-by-step explanation:
* Lets explain how to solve the problem
- Four 3 megawatt wind turbines can supply enough electricity
to power 3000 homes
∴ The number of turbines is 4
∵ Each turbine give 3 megawatt
∴ The four turbines give ⇒ 4 × 3 = 12 megawatt
- This quantity give enough electricity to power 3000 homes
∴ The number of homes for the 12 megawatt is 3000
- We need to find how many turbines can cover enough electricity
to power 55,000 homes, so we must to know the quantity of
electricity that be enough to power 55,000 homes
* <em>Lets use the cross multiplication to solve the problem</em>
∵ megawatt : number of homes
12 : 3,000
? : 55,000
- <em>By using cross multiplication</em>
∴
∴ The enough electricity to power 3000 homes = 220 megawatt
∵ Each turbine gives 3 megawatt
- Find the number of turbines divides the total megawatt by the the
megawatt of one turbine
∴ The number of turbines = 220 ÷ 3 = 73.3
- If we take 73 only the electricity will not be enough to cover all
homes, so we must to take 74 turbines
∴ The number of turbines is 74
Answer:
P(x=2) = 0.2368
Step-by-step explanation:
given data
stocks of local interest N = 20
stocks increased K = 10
stocks decreased = 5
remained unchanged = 5
solution
we take here no of stock that are increased randomly n = 2
so here Hypergeometric random variable can take integer value
{max(0, n+k - N ), min(n,K) } = {0,2}
so here
P(x=2)
so
P(x=k) = .......................1
P(x=2 ) =
solve it we get
P(x=2 ) = 0.236842
now we use excel function as
HYPGEOM.DIST (k,n,N.cumulative) .....................2
so it will be
HYPGEOM.DIST (2,2,10,,false)
we get
HYPGEOM.DIST (2,2,10,,false) = 0.236842
so
P(x=2) = 0.2368