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liberstina [14]
2 years ago
12

I've been stuck on this for so long and I have an exam soon, anybody who can help me :'( ?

Mathematics
1 answer:
san4es73 [151]2 years ago
8 0
(i)  speed = distance / time
so time =  distance / speed
here we have

time t = 1080/x  hours

(ii) return flight  time  = 1080 / (x + 30)  hours

(a)  1080/x - 1080/(x + 30) = 1/2

Multiplying  through by the LCD 2x(x + 30) we get:-

1080*2(x + 30) - 2x*1080 = x(x+30)
2160x + 64800 - 2160x = x^2 + 30x
x^2 + 30x - 64800  = 0

(b)  factoring;  -64800 = 270 * -240  ans 270-240 = 30 so we have

(x + 270)(x - 240) = 0   so x = 240  ( we ignore the negative -270)

So the speed for outward journey is 240 km/hr

(c) time ffor outward flight = 1080 / 240 =  4 1/2  hours

(d) average speed for whole flight = distance / time
   Time for outward journey = 4.5 hours and time for  return journey = d / v
= 1080 / (240+30) =  4 hours
 Therefore the average speed for whole journey =  2160 / 8.5 = 254.1 km/hr
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valkas [14]

Answer:

a = $31.23 per month

b = $20.83 per month

c = 249.98 = $249.98 interest charges

                   = $624-249.98 = 374.02 profit part decrease 8% inc.                  

d = 35.35%

e = Answer is in the name; basic payment is a contract which means whilst account remains open charges are requested without fail. Should balance be less or on zero, charges are still applied.

Step-by-step explanation:

2500 x 1.2499 = interest only for start month 13 =3124.75

3124.75/ 100 x 1.08   = 8% of this = 249.98 each year.

We only have to divide each by 12 to work out monthly individual charges and subtract to find out payments.

3124.75 - 249.98 = 2874.77 = Total after charges each year.

249.98/12 = 20.83 = monthly charges.

3124.75- 2500 = 624.75 payments each year

624.75/12 = 52.06 month 1 payment before charge

52.06-20.83 =31.23 total minimum payment

2500 + 249.98

Percentage = 200:600 = 1/3 33% + (comparing to ratio 10:25 closer to 40%)

We find ratio 200:600= 33.33 + 49.995/24.75 = 2.02

33+2.02 = 35.35%

7 0
2 years ago
You have an ant farm with 31 ants. The population of ants in your farm will double every 3 months. The table shows the populatio
Evgesh-ka [11]

Answer:

I think the table is linear. The total amount after one year is 248 ants.

Step-by-step explanation:

8 0
1 year ago
A sample of size 60 from one population of weights had a sample average of 10.4 lb. and a sample standard deviation of 2.7 lb. A
Olegator [25]

Answer:

z=  0.278

Step-by-step explanation:

Given data

n1= 60 ; n2 = 100

mean 1= x1`= 10.4;     mean 2= x2`= 9.7

standard deviation  1= s1= 2.7 pounds ;  standard deviation 2= s2 = 1.9 lb

We formulate our null and alternate hypothesis as

H0 = x`1- x`2 = 0 and H1 = x`1- x`2 ≠ 0 ( two sided)

We set level of significance α= 0.05

the test statistic to be used under H0 is

z = x1`- x2`/ √ s₁²/n₁ + s₂²/n₂

the critical region is z > ± 1.96

Computations

z= 10.4- 9.7/ √(2.7)²/60+( 1.9)²/ 100

z= 10.4- 9.7/ √ 7.29/60 + 3.61/100

z= 0.7/√ 0.1215+ 0.0361

z=0.7 /√0.1576

z= 0.7 (0.396988)

z= 0.2778= 0.278

Since the calculated value of z does not fall in the critical region so we accept the null hypothesis H0 = x`1- x`2 = 0  at 5 % significance level. In other words we conclude that the difference between mean scores is insignificant or merely due to chance.

3 0
2 years ago
Solve x2 = 12x – 15 by completing the square. Which is the solution set of the equation?
Nady [450]
For this case we have the following polynomial:
 x ^ 2 = 12x - 15

 The first thing to do is to place the variables on the same side of the equation.
 We have then:
 x ^ 2 - 12x = -15

 We complete the square by adding the term (b / 2) ^ 2 on both sides of the equation.
 We have then:
 x ^ 2 - 12x + (-12/2) ^ 2 = -15 + (-12/2) ^ 2

 Rewriting we have:
 x ^ 2 - 12x + (-6) ^ 2 = -15 + (-6) ^ 2

x ^ 2 - 12x + 36 = -15 + 36
 
(x-6) ^ 2 = 21
 x-6 =+/- \sqrt{21}
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 x = 6 - \sqrt{21}
 x = 6 + \sqrt{21}
 Answer:
 
the solution set of the equation is:
 
x = 6 - \sqrt{21}
 x = 6 + \sqrt{21}
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2 years ago
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