Answer:
Algebraic expression ; 3x = 39
Step-by-step explanation:
Let the unknown number be x

Further solving

(a) We need to figure out the deciles for a normal distribution curve in this part.
In order to do so, we need to find the z score corresponding to probability 0.10 and 0.90 on the normal distribution curve.
Upon looking at the normal distribution table, we can see that the probability P = 0.10 corresponds to a z score of -1.28 and probability P = 0.90 corresponds to a z score of 1.28.
Therefore, deciles are -1.28 and 1.28 for a normal distribution curve.
(b) In this part, we are given that mean height is 69.5 inches and standard deviation in height is 2.7 inches. Therefore, we can find the deciles using the z score formula as shown below:

Therefore, the required deciles are 66.044 and 72.956
When you're subtracting negatives, you're adding them so... Here's a tip:
-9 - (-83)
So..
-9 + (-83) = -92
To find the total area of the octagon you can find the area of the rectangle that is created by the entire figure and subtract the areas of the four congruent right triangles.
(10 cm x 6 cm) - [4(1/2 x 2 x 2)]
60 cm² -8 cm² = 52 cm²
The total area of the octagon is 52 cm².
answer:20 min. each
Step-by-step explanation:
2*60=120
120/6=20