The mean is calculated by adding up all of the given numbers and dividing by the number of numbers.
Lets, for ease of understanding, say that the first three number were 64...
Mean=(64+64+64)/3=192/3=64
Now, lets solve for the mean where 'x' is the unknown fourth number and 128 is the mean. (since, the answer said that when the fourth number was added the mean, 64, was doubled '64*2=128')
128=(64+64+64+x)/4
128=(192+x)/4
Multiply both sides by 4
512=192+x
subtract 192 from both sides
320=x
The missing number is 320..
Now lets double check our work.
Mean=(64+64+64+320)/4=512/4=128
Answer=320
Answer:
x = 0.1, y = 0.075
Step-by-step explanation:
Given the 2 equations
27x + 24y = 4.5 → (1)
1.5x + y = 0.225 → (2)
Multiplying (2) by - 24 and adding to (1) will eliminate the y- term
- 36x - 24y = - 5.4 → (3)
Add (1) and (3) term by term to eliminate y
- 9x = - 0.9 ( divide both sides by - 9 )
x = 0.1
Substitute x = 0.1 into either of the 2 equations and solve for y
Substituting into (2)
1.5(0.1) + y = 0.225
0.15 + y = 0.225 ( subtract 0.15 from both sides )
y = 0.075
Answer:
ABC~WXY by AA
Step-by-step explanation:
In ΔABC
∠B = 90°
∠A = 27°
To Find ∠C
Angle sum property: The sum of all angles of triangle is 180°
∠A+∠B+∠C=180°
27°+90°+∠C=180°
∠C=180°-117°
∠C=63°
In ΔWXY
∠X = 90°
∠Y = 63°
We will use angle sum property
So, ∠W+∠Y+∠X=180°
90°+63°+∠W=180°
∠W=180°-(90°+63°)
∠W=27°
So, ∠A=∠W
∠B =∠X
∠C = ∠Y
So, ABC~WXY by Angle - Angle property.
Hence ABC~WXY by AA
