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olga_2 [115]
3 years ago
11

Please help me in this question

Mathematics
1 answer:
charle [14.2K]3 years ago
6 0
Number defective=4
number of non-defective=total-defective
=20-4
=16
the questions asked for 1 defective
so we choose only 1 defective from 4 defective items
4C1

and for 1 non-defective
we choose only 1 non-defective from 16 non-defective items
16C1

we choose 2 items from 20 items
so 20C2

answer:
probability= [(4C1) * (16C1)] /(20C2)
=32/95

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A 12 ft ladder leans against the side of a house. The top of the ladder is 10ft off the ground. Find x, the angle of elevation o
attashe74 [19]

The image is missing, so i have attached it.

Answer:

x = 56.44°

Step-by-step explanation:

From the attached image, we can see that this is a right angle triangle which has opposite, adjacent and hypotenuse as sides. Since we want to find the angle x, thus, we can make use of trigonometric ratios.

From the attached image, the side opposite to angle x is 10ft and the hypotenuse is 12 ft.

From trigonometric ratios, we know that, sin x = opposite/hypotenuse

So, sin x = 10/12

x = sin^(-1) (10/12)

x = sin^(-1) 0.8333

x = 56.44°

6 0
4 years ago
Bess wants to find the favorite sports of students at her school. How can she choose a sample for her survey?
Dmitrij [34]
She can make a vote around the school
5 0
4 years ago
Read 2 more answers
The distance travelled in (m) by a ball dropped from a height are 128/9,32/3,8,6,...
Allushta [10]

Answer: it will trave 56.89 meters before coming to rest.

Step-by-step explanation:

This is a geometric progression since the distance travelled (height) by the ball is reducing by a constant ratio, r. Since the number of times that the ball will bounce is infinite, then we would apply the formula for determining the sum of the terms in a geometric progression to infinity which is expressed as

S = a/(1 - r)

where

S = sum of the distance travelled by the ball

a = initial distance or height of the ball

r = common ratio

From the information given,

a = 128/9

r = (32/3)/(128/9) = 0.75

Therefore,

S = (128/9)/(1 - 0.75) = 56.89 meters

7 0
3 years ago
Olivia flips a two-sided counter and then spins a spinner with six equal-size sections labeled 1 through 6. One side of the coun
Novay_Z [31]

Answer:

12

Step-by-step explanation:

A 2 - sided counter ; (red, yellow)

A spinner (1,2,3,4,5,6)

Number of trials = 80

P(red and number > 3) :

P(red) = 1/2 ;

P(number >3) : numbers greater Than 3 = (4, 5, 6)

Hence, P(number <3) = 3 /6 = 1/2

Theoretical probability = 1/2 *1/2 = 1/4

Expected number of outcomes :

1/4 * number of trials

1/4 * 80 = 20

Experimental outcome :

Relative frequency = number of outcomes / number of trials

Relative frequency = 2/5

Hence,

2/5 = number of outcomes / 80

Cross multiply :

160 = number of outcomes * 5

Number of outcomes = 160 /5 = 32

Actual outcomes = 32

Difference between actual and expected :

32 - 20 = 12

7 0
3 years ago
2. Determine the sum of the first 400 ODD numbers.<br><br>​
il63 [147K]

Odd numbers take the form 2n-1, where n\ge1 is an integer. When n=400, the last odd number would be 799. So we're adding

S=1+3+5+\cdots+795+797+799

By reversing the order of terms, we have

S=799+797+795+\cdots+5+3+1

and we can pair up terms in both sums at the same position to write

2S=(1+799)+(3+797)+(5+795)+\cdots(795+5)+(797+3)+(799+1)

so that we are basically adding 400 copies of 800, and from there we can find the value of the sum right away:

2S=400\cdot800\implies S=160,000

###

We could also make use of the formulas,

\displaystyle\sum_{i=1}^n1=n

\displaystyle\sum_{i=1}^ni=\dfrac{n(n+1)}2

We have

S=\displaystyle\sum_{i=1}^{400}(2i-1)=2\sum_{i=1}^{400}i-\sum_{i=1}^{400}1=400(400+1)-400=400^2=160,000

3 0
4 years ago
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