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3 years ago

Four brothers and their sister have the average age 7. Four brothers have the average age 6. How old is the sister?

Mathematics

1 answer:

AnnyKZ [126]3 years ago

4 0

Answer:

11 years old

Step-by-step explanation:

If four brothers have the average age 6, then the sum of their ages is

$4\cdot 6=24$

years.

Let x years be the age of sister. If four brothers and their sister have the average age 7, then

$\dfrac{24+x}{5}=7.$

Multiply this equation by 5:

$24+x=35\Rightarrow x=35-24=11.$

The sister is 11 years old.

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Which solid has a greater volume

Triss [41]

Answer:

The volume of cylinder and the volume of a cone, have equal volume measurements. So, the answer is C).

Step-by-step explanation:

Cylinder:

-Use the formula for the volume of a cylinder. Use both the radius and height for the formula in order to solve and get the volume:

$V = \pi r^2 h$

$V = \pi 2^2 6$

-Solve:

$V = \pi 2^2 6$

$V = \pi \times 2^2 \times 6$

$V = \pi \times 4 \times 6$

$V = \pi \times 24$

$V = 24\pi \approx 75.39$

--------------------------------------------------------------------------------------------------------

Cone:

-Use the formula for the volume of a cone and the radius and height for the formula and solve the formula to get the volume:

$V = \frac{1}{3} \pi r^2h$

$V = \frac{1}{3} \pi 3^28$

-Solve:

$V = \frac{1}{3} \pi 3^28$

$V = \frac{1}{3} \times \pi \times 3^2 \times 8$

$V = \frac{1}{3} \times \pi \times 9 \times 8$

$V = \frac{1}{3} \times \pi \times 72$

$V = \frac{1}{3} \pi \times 72$

$V = 24\pi \approx 75.39$

-So, according to the volume of a cylinder and the volume of a cone, They both have the same volume.

Cylinder: $75.39$ $ft^3$

Cone: $75.39$ $ft^3$

5 0

3 years ago

Plz help with this problem! x^4 + x^2 + 1

TEA [102]

Answer:

You cannot simplify this problem down anymore; it is at its simplest form.

Step-by-step explanation:

You cannot add together x^4 and x^2 due to the simple fact that they do not share similar exponents.

For example you could add together x^4 and x^4 to get 2x^4. But you cannot add x^4 and x^2.

7 0

3 years ago

A desk is 2 meters long and 1 meter wide. The desk needs to be represented in a scale drawing of an office that uses a scale of

Strike441 [17]

Answer:

Thus, the dimensions of the desk in the drawing are 4 cm long and 2 cm wide.

Step-by-step explanation:

Scaling

The scale factor established to represent a desk 2 meters long and 1 meter wide is:

1 centimeter = 0.5 meter

We need to convert the real dimensions to the scaled dimensions. To complete the task, it's a good idea to multiply the real dimensions by the ratio:

$\displaystyle \frac{1\ cm}{0.5\ m}$

to get the scaled dimensions.

The length of 2 meters is scaled to:

$\displaystyle 2\ m\frac{1\ cm}{0.5\ m}=4\ cm$

And the width of 1 meter is scaled to:

\displaystyle 1\ m\frac{1\ cm}{0.5\ m}=2 cm

Thus, the dimensions of the desk in the drawing are 4 cm long and 2 cm wide.

3 0

2 years ago

The Dewey Civic Center has 1,600 seats. Tickets for 85% of the total number of seats were sold. How many tickets were sold?

Juliette [100K]

1600×85%=1360 I think that 1360 Tickets were sold

4 0

3 years ago

8. A box is filled with candies in different colors. We have 40 white candies, 24 green ones, 12

Darya [45]

Answer:

$P(Green\ or\ Red) = 0.30$

Step-by-step explanation:

Given

$White = 40$

$Green = 24$

$Red = 12$

$Yellow = 24$

$Blue = 20$

Required

$P(Green\ or\ Red)$

The total numbe of candy is:

$Total = 40 + 24 + 12 + 24 + 20$

$Total = 120$

This probability is calculated as:

$P(Green\ or\ Red) = P(Green) + P(Red)$

For each, we have:

$P(Green\ or\ Red) = \frac{Green}{Total} + \frac{Red}{Total}$

Take LCM

$P(Green\ or\ Red) = \frac{Green+Red}{Total}$

$P(Green\ or\ Red) = \frac{24+12}{120}$

$P(Green\ or\ Red) = \frac{36}{120}$

$P(Green\ or\ Red) = 0.30$

8 0

3 years ago