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tatiyna
3 years ago
13

Need help with maths ASAP

Mathematics
1 answer:
givi [52]3 years ago
8 0

Answer:

a = 7

b = 3

Step-by-step explanation:

So you can come up with 2 equations.

a(9 + b) = 84

ab = 21

On the first equation, divide by 9 + b on both sides.

a=\frac{84}{9+b}

n the second equation, divide by b on both sides.

a=\frac{21}{b}

Now you can set them equal and solve for b.

\frac{84}{9+b}=\frac{21}{b}

Cross multiply:

84b = 189 + 21b

63b = 189

b = 3

a = 7

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A business school has a goal that the average number of years of work experience of its MBA applicants is more than three years.
gizmo_the_mogwai [7]

Answer:

z=\frac{3.1-3}{\frac{2.449}{\sqrt{47}}}=0.280    

p_v =P(z>0.280)=0.390  

If we compare the p value and the significance level assumed \alpha=0.01 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can't conclude that the height of men actually its NOT significant higher than 0.3 at 1% of signficance.  

Step-by-step explanation:

Data given and notation  

\bar X=3.1 represent the sample mean

\sigma=\sqrt{6} represent the sample standard deviation for the sample

n=47 sample size  

\mu_o =3 represent the value that we want to test

\alpha represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

p_v represent the p value for the test (variable of interest)  

State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the mean is higher than 3, the system of hypothesis would be:  

Null hypothesis:\mu \leq 3  

Alternative hypothesis:\mu > 3  

If we analyze the size for the sample is > 30 and we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:  

z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}  (1)  

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  

Calculate the statistic

We can replace in formula (1) the info given like this:  

z=\frac{3.1-3}{\frac{2.449}{\sqrt{47}}}=0.280    

P-value

Since is a one side test the p value would be:  

p_v =P(z>0.280)=0.390  

Conclusion  

If we compare the p value and the significance level assumed \alpha=0.01 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can't conclude that the height of men actually its NOT significant higher than 0.3 at 1% of signficance.  

3 0
3 years ago
The nth term of a sequence is n^2 -n-2 .find the sum of the first and third terms
Troyanec [42]

Answer:

2

Step-by-step explanation:

substitute n=1 and n=3 in the given equation

1 st term is (1)^2-1-2 = 1 -1 -2 = -2

3rd term is (3)^2-3-2 = 9-3-2=4

sum of 1st and 3rd term is -2 + 4 = 2

8 0
3 years ago
In a school, the ratio of soccer players to volleyball players is 4 : 1.
VLD [36.1K]
4:1 means for every four soccer player there is 1 volleyball player

that means there are four times the number of soccer players than volleyball players
7 0
3 years ago
Find the slope of each line.<br><br> PLEASE HELP!!! 15 PTS!!!
leva [86]

Answer:

im pretty sure its -3/2

Step-by-step explanation:

since you have to do rise over run and your falling 3 so its a negative 3 and you always run right so its run 2 so then its -3/2 if its not that sorry

5 0
2 years ago
How many even 5-digit numbers can be formed from the numbers 1, 2, 4, 7, 8 if no digit is repeated in a number? A. 72 B. 120 C.
katovenus [111]
Hello,

Let's place the last digit: it must be 2 or 4 or 8 (3 possibilities)

It remainds 4 digits and the number of permutations fo 4 numbers is 4!=4*3*2*1=24

Thus there are 3*24=72 possibilities.

Answer A

If you do'nt believe run this programm

DIM n(5) AS INTEGER, i1 AS INTEGER, i2 AS INTEGER, i3 AS INTEGER, i4 AS INTEGER, i5 AS INTEGER, nb AS LONG, tot AS LONG
tot = 0
n(1) = 1
n(2) = 2
n(3) = 4
n(4) = 7
n(5) = 8
FOR i1 = 1 TO 5
    FOR i2 = 1 TO 5
        IF i2 <> i1 THEN
            FOR i3 = 1 TO 5
                IF i3 <> i2 AND i3 <> i1 THEN
                    FOR i4 = 1 TO 5
                        IF i4 <> i3 AND i4 <> i2 AND i4 <> i1 THEN
                            FOR i5 = 1 TO 5
                                IF i5 <> i4 AND i5 <> i3 AND i5 <> i2 AND i5 <> i1 THEN
                                    nb = ((((n(i1) * 10) + n(i2)) * 10 + n(i3)) * 10 + n(i4)) * 10 + n(i5)
                                    IF nb MOD 2 = 0 THEN
                                        tot = tot + 1
                                    END IF
                                END IF
                            NEXT i5
                        END IF
                    NEXT i4
                END IF
            NEXT i3
        END IF
    NEXT i2
NEXT i1
PRINT "tot="; tot
END


7 0
3 years ago
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