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likoan [24]
3 years ago
8

7. There are 12 singers auditioning for the school musical. In how many ways can the director choose first a lead singer and the

n a stand-in for the lead singer?
Mathematics
1 answer:
Finger [1]3 years ago
8 0

Answer: The director can choose first a lead singer and then a stand-in for the lead singer in 132 ways.

Step-by-step explanation:

Given : The total number of singers auditioning for the school musical.= 12

The director wanted choose first a lead singer and then a stand-in for the lead singer.

We use Permutations here because order of selecting the singers matters.

The number of permutations of selecting r things out of n things = ^nP_r=\dfrac{n!}{(n-r)!}

Similarly , the number of ways to select 2 singers in an order from 12 singers

^{12}P_{2}{=\dfrac{12!}{(12-2)!}

=\dfrac{12\times11\times10!}{10!}=132

Hence, the director can choose first a lead singer and then a stand-in for the lead singer in 132 ways.

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A bag contains Red, Green and Yellow balls. A ball is taken at random from the bag. The probability that it is Red is 0.35 and t
Eddi Din [679]

Answer:

  • P(Yellow)=0.25
  • P(Not Red)=0.65

Step-by-step explanation:

P(Red)=0.35

P(Green)=0.4

(a)Since there are three colours inside the bag

P(Red)+P(Green)+P(Yellow)=1

0.35+0.4+P(Yellow)=1

P(Yellow)=1-(0.35+0.4)

P(Yellow)=0.25

(b) In probability, the sum of an event and its complement is 1.

Therefore:

P(Red)+P(Not Red)=1

0.35+P(Not Red)=1

P(Not Red)=1-0.35

P(Not Red)=0.65

3 0
3 years ago
Two similiar rectangles have corresponding sides in the ratio 10:3. What is the ratio of their areas
lianna [129]

Answer:

Step-by-step explanation:

The ratio of its areas is equal to

Step-by-step explanation:

we know that

If two figures are similar, then the ratio of its areas is equal to the scale factor squared

In this problem the scale factor is equal to the ratio 10:3

Let

z-------> the scale factor

so

z2=(10/3)2=100/9

7 0
3 years ago
The equations y = 30x + 10 and y = –x2 + 150x + 10 model the daily sales of two car models, where x represents the number of day
yuradex [85]

Answer:

  day 0, day 120

Step-by-step explanation:

You want to find the value of x that makes both y-values be the same:

  y = y

  30x +10 = -x^2 +150x +10

  x^2-120x = 0 . . . . subtract the right side of the equation

  x(x -120) = 0 . . . . . factor

Values of x that make this true are x=0 and x=120.

The same number of each car was sold on day 0 and day 120.

7 0
3 years ago
Dave has $8000 to invest for 15 years. He finds a bank that offers an interest rate of 3.1% compounded monthly. How much money w
ioda

Dave will have $12,728 after 15 years, if he has $8000 to invest for 15 years. He finds a bank that offers an interest rate of 3.1% compounded monthly.

Step-by-step explanation:

The given is,

                 Investment = $ 8000

               No. of years = 15 years

             Interest rate, i = 3.1 %

                 ( compounded monthly )  

Step:1

          For for calculating future value with compound interest monthly,

                                     A = P (1 +\frac{r}{n})^{nt}.................(1)

         Where,

                     A = Future amount

                     P = Initial investment

                     r = Rate of interest

                    n = Number of compounding in a year

                     t = Time period

Step:2

           From given values,

                           P = $8000

                            r =  3.1%

                            t = 15 years

                            n = 12 ( for monthly)

           Equation (1) becomes,

                          A = 8000( 1+\frac{0.031}{12} )^{(12)(15)}

                              = 8000 (1+0.002583)^{180}

                              = 8000(1.002583)^{180}

                              = 8000(1.591059)

                              =12728.48

                           A = $ 12728.48

Result:

           Dave will have $12,728 after 15 years, if he has $8000 to invest for 15 years. He finds a bank that offers an interest rate of 3.1% compounded monthly.

                             

       

8 0
3 years ago
Identify the rule that could possibly describe this set of data.
Elina [12.6K]

option D is the correct option

y= 10- 2x

Now, if we take the first value of x i.e 1

then, y= 10-2(1)

= 10-2 = 8 ---------> this value matches with the given value of y

take,x =2

y=10-2(2) = 10-4 = 6--------->this value matches with the given value of y

taking, x = 3

y= 10-2(3) = 10- 6=4-------->this value matches with the given value of y

7 0
3 years ago
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