Will mark as brainliest if correct

Please help me to figure out this question. Thanks

Marta_Voda [28]

Answer:

a) 5 : 7

b) 25 black keys

c) 100 black keys will appear.

Step-by-step explanation:

a) From the picture,

There are 5 black keys and 7 white keys.

Therefore, the ratio of black keys to white keys are = 5 : 7 = 5/7

b) If the pattern continues, 25 black keys will be appeared on a portable full-sized keyboard.

Explanation -

From part A, we get the ratio of black keys to white keys = 5 : 7. Therefore,

If there are 7 white keys, there are 5 black keys

If there are 1 white keys, there are 5/7 black keys

If there are 35 white keys, there are (5*35)/7 black keys

= 25 black keys.

c) If there are 240 keys, the black keys will appear -

We get, the ratio of black keys to white keys = 5 : 7

The summation of the black keys and white keys = (5 + 7) = 12.

Therefore, if there are 240 keys, the black keys will be

= (5/12) x 240

= (5 x 240)/12

= 100

Therefore, there are 100 black keys.

7 0

3 years ago

What is (4x+1)(2x-1)

Semmy [17]

I think the answer is 8x. I am not 100% sure

5 0

2 years ago

The diameter of a wheel from a bicycle is 66 CM about how far will the wheel travel in one turn

castortr0y [4]

Answer:

If the outside diameter of the wheel is 66cm, it will travel 1 wheel circumference. Circumference is Pi x diameter = 3.14 x 66 = 207.24 cm.Step-by-step

Explanation:

If the diameter is of the wheel (without the tire) you need to calculate the actual diameter from the outermost edge of the tire.

8 0

2 years ago

True or false? I'm deductive thinking, you start with a given set of rules and conditions and determine what must be true as a c

aksik [14]

Deductive thinking: When you start with a given set of rules and conditions and determine what must be true as a consequence.

So the answer is true.

7 0

3 years ago

Steve likes to entertain friends at parties with "wire tricks." Suppose he takes a piece of wire 60 inches long and cuts it into

Alex_Xolod [135]

Answer:

a) the length of the wire for the circle = $(\frac{60\pi }{\pi+4}) in$

b)the length of the wire for the square = $(\frac{240}{\pi+4}) in$

c) the smallest possible area = 126.02 in² into two decimal places

Step-by-step explanation:

If one piece of wire for the square is y; and another piece of wire for circle is (60-y).

Then; we can say; let the side of the square be b

so 4(b)=y

b= $\frac{y}{4}$

Area of the square which is L² can now be said to be;

$A_S=(\frac{y}{4})^2 = \frac{y^2}{16}$

On the otherhand; let the radius (r) of the circle be;

2πr = 60-y

$r = \frac{60-y}{2\pi }$

Area of the circle which is πr² can now be;

$A_C= \pi (\frac{60-y}{2\pi } )^2$

$=( \frac{60-y}{4\pi } )^2$

Total Area (A);

A = $A_S+A_C$

= $\frac{y^2}{16} +(\frac{60-y}{4\pi } )^2$

For the smallest possible area; $\frac{dA}{dy}=0$

∴ $\frac{2y}{16}+\frac{2(60-y)(-1)}{4\pi}=0$

If we divide through with (2) and each entity move to the opposite side; we have:

$\frac{y}{18}=\frac{(60-y)}{2\pi}$

By cross multiplying; we have:

2πy = 480 - 8y

collect like terms

(2π + 8) y = 480

which can be reduced to (π + 4)y = 240 by dividing through with 2

$y= \frac{240}{\pi+4}$

∴ since $y= \frac{240}{\pi+4}$ , we can determine for the length of the circle ;

60-y can now be;

= $60-\frac{240}{\pi+4}$

= $\frac{(\pi+4)*60-240}{\pi+40}$

= $\frac{60\pi+240-240}{\pi+4}$

= $(\frac{60\pi}{\pi+4})in$

also, the length of wire for the square (y) ; $y= (\frac{240}{\pi+4})in$

The smallest possible area (A) = $\frac{1}{16} (\frac{240}{\pi+4})^2+(\frac{60\pi}{\pi+y})^2(\frac{1}{4\pi})$

= 126.0223095 in²

≅ 126.02 in² ( to two decimal places)

4 0

3 years ago