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3 years ago

A car park charges a certain rate per hour before 3 pm, and a higher rate per hour

Mathematics

1 answer:

taurus [48]3 years ago

4 0

Who's JD? I'll guess that's money in some country.

This one requires a bit of analysis before writing the equation. 3pm is the time the price changes so

11am to 5 is 4 hours before, 2 hours after, JD18

9am to 7 is 6 hours before, 4 hours after, JD31

OK, let's call the morning rate x and the evening rate y.

Rate times hours is cost; we have to add up the morning and evening:

4x + 2y = 18

6x + 4y = 31

We multiply the first equation by 2,

8x + 4y = 36

Subtract the second equation,

2x = 36 - 31 = 5

x = 5/2

2y = 18 - 4x

y = 9 - 2x = 9 - 5 = 4

Answer: Our solution is the price was JD 2.50 before 3pm and JD 4 after.

Check:

2.5(4) + 4(2) = 18 good

2.5(6) + 4(3) = 31 good

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there are 3 liters of apple juice at a school party. 10 students want to drink all the apple juice, Andi all want to get exactly

pochemuha

Answer:

0.3 L

Step-by-step explanation:

3 L / 10 students = 3/10 = 0.3 Liters per student

4 0

3 years ago

In two or more complete sentences, compare the number of x-intercepts in the graph of f(x) = x2 to the number of x-intercepts in

TEA [102]

F(x) has only one x-intercept when x=0

g(x)=-x^2-6

g(x)=-(x^2+6) so g(x) will have no x-intercepts as its maximum value will be -6.

g(x) is f(x) reflected about the x axis and shifted downwards by 6 units.

6 0

3 years ago

Solve this equation for x: 2x^2 + 12x - 7 = 0

zhannawk [14.2K]

Answer:

x=0.5355 or x=-6.5355

First step is to: Isolate the constant term by adding 7 to both sides

Step-by-step explanation:

We want to solve this equation: $2x^2 + 12x - 7 = 0$

On observation, the trinomial is not factorizable so we use the Completing the square method.

Step 1: Isolate the constant term by adding 7 to both sides

$2x^2 + 12x - 7+7 = 0+7\\2x^2 + 12x=7$

Step 2: Divide the equation all through by the coefficient of $x^2$ which is 2.

$x^2 + 6x=\frac{7}{2}$

Step 3: Divide the coefficient of x by 2, square it and add it to both sides.

Coefficient of x=6

Divided by 2=3

Square of 3= $3^2$

Therefore, we have:

$x^2 + 6x+3^2=\frac{7}{2}+3^2$

Step 4: Write the Left Hand side in the form $(x+k)^2$

$(x+3)^2=\frac{7}{2}+3^2\\(x+3)^2=12.5\\$

Step 5: Take the square root of both sides and solve for x

$x+3=\pm\sqrt{12.5}\\x=-3\pm \sqrt{12.5}\\x=-3+ \sqrt{12.5}, $ or $x= -3- \sqrt{12.5}\\$x=0.5355 or x=-6.5355$

6 0

3 years ago

A sleep time of 15.9 hours per day for a newborn baby is at the 10h percentile of the distribution of sleep times for all newbor

Nuetrik [128]

Answer:

option (D) 16.5

Step-by-step explanation:

Data provided:

Sleep time of , X = 15.9 is at the 10th percentile

Standard deviation, σ = 0.5 hour

also,

10th percentile of normal distribution is

Z = F⁻¹(0.10)

Z = - 1.28 (Using Standard Normal distribution)

Now,

$\\Z=\frac{X-\mu}{\sigma}$

X = μ + ( σ × Z )

μ = X - ( σ × Z )

on substituting the respective values, we get

μ = 15.9 - 0.5 × (-1.28)

μ = 16.5

Hence, the correct answer is option (D) 16.5

8 0

3 years ago

5.676524687 in fraction

Ugo [173]

Answer:

5 7/10

Step-by-step explanation:

First, we need to round the number.

5.7

Now that we've rounded the number we can convert it to a fraction based on where the decimal is located.

5.7

Tenths

So, the decimal is in the tenths that means we have to put 7 over 10.

5 7/10

Hope this helps! :)

6 0

3 years ago