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2 years ago

One type of lightning bug glows once every 1 1/2 seconds. How many times can it glow in 1 minute?

Mathematics

2 answers:

KIM [24]2 years ago

8 0

It can glow 40 times per minute

Travka [436]2 years ago

5 0

40 times per minute. Divide 60 by 1.5.

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Please teach me on how to answer this question. (addmath question)

arsen [322]

We know that $\overline{x}=8$ so:

$\overline{x}=8\\\\\\\dfrac{\sum\limits_{k=1}^7\,x_k}{7}=8\qquad|\cdot7\\\\\\ \boxed{\sum\limits_{k=1}^7\,x_k=56}$

We want to calculate:

$\sum\limits_{k=1}^7\,\big(2x_k-3\big)^2=\sum\limits_{k=1}^7\,\big(4x_k^2-12x_k+9\big)=\\\\\\=\sum\limits_{k=1}^7\,4x_k^2-\sum\limits_{k=1}^7\,\big12x_k+\sum\limits_{k=1}^7\,9=4\sum\limits_{k=1}^7\,x_k^2-12\sum\limits_{k=1}^7\,x_k+\sum\limits_{k=1}^7\,9=\\\\\\=4\cdot672-12\cdot56+7\cdot9=2688-672+63=\boxed{2079}$

5 0

2 years ago

Please help with b if you understand

vagabundo [1.1K]

I believe if I'm correct the answer is 2a 3b 4c

0 ? f

Sorry I couldn't figure out the one with the question mark.

7 0

3 years ago

Pleaseeeeeee help me

alekssr [168]

Answer:

-56

Step-by-step explanation:

(6 ✕–8) – 8

–48–8

= –56

3 0

2 years ago

Name the types of angles shown.

OlgaM077 [116]

Answer:

C) supplementary angles

D) straight angle

Step-by-step explanation:

There is a straight line, and when an angle is a straight it means its 180 degrees which makes it a supplementary angle and a straight angle.

There are no angles that are 90 degrees so its not complementary or a right angle.

7 0

3 years ago

Read 2 more answers

A rectangle has an area of 19.38 cm2. When both the length and width of the rectangle are increased by 1.50 cm, the area of the

Lostsunrise [7]

Answer: $5.7\ cm$

Step-by-step explanation:

Given

Rectangle has an area of $19.38\ cm^2$

Suppose rectangle length and width are $l$ and $w$

If each side is increased by $1.50\ cm$

Area becomes $A_2=35.28\ cm^2$

We can write

$\Rightarrow lw=19.38\quad \ldots(i)\\\\\Rightarrow (l+1.5)(w+1.5)=35.28\\\Rightarrow lw+1.5(l+w)+1.5^2=35.28\\\text{use (i) for}\ lw\\\Rightarrow 19.38+1.5(l+w)=35.28-2.25\\\Rightarrow l+w=9.1\quad \ldots(ii)$

Substitute the value of width from (ii) in equation (i)

$\Rightarrow l(9.1-l)=19.38\\\Rightarrow l^2-9.1l+19.38=0\\\\\Rightarrow l=\dfrac{9.1\pm\sqrt{(-9.1)^2-4(1)(19.38)}}{2\times 1}\\\\\Rightarrow l=\dfrac{9.1\pm\sqrt{5.29}}{2}\\\\\Rightarrow l=\dfrac{9.1\pm2.3}{2}\\\\\Rightarrow l=3.4,\ 5.7$

Width corresponding to these lengths

$w=5.7,\ 3.4$

Therfore, we can write the length of the longer side is $5.7\ cm$

8 0

3 years ago