How do you write 0.000081 in scientific notation?

How many 4 minutes and 30 seconds in 2 hours

AleksAgata [21]

4 minutes and 30 seconds go into 2 hours 26 times

119

7 0

4 years ago

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HALLP QUICKKKK

Rina8888 [55]

To solve this we are going to use the formula for speed: $S= \frac{d}{t}$
where
$S$ is the speed
$d$ is the distance
$t$ is the time

Let $S_{l}$ be the speed of the boat in the lake, $S_{a}$ the speed of the boat in the river, $t_{l}$ the time of the boat in the lake, and $t_{a}$ the time of the boat in the river.

We know for our problem that the current of the river is 2 km/hour, so the speed of the boat in the river will be the speed of the boat in the lake minus 2km/hour:
 $S_{a}=S_{l}-2$
We also know that in the lake the boat sailed for 1 hour longer than it sailed in the river, so:
 $t_{l}=t_{a}+1$

Now, we can set up our equations.
Speed of the boat traveling in the river:
 $S_{a}= \frac{6}{t_{a} }$
But we know that $S_{a}=S_{l}-2$ , so:
$S_{l}-2= \frac{6}{t_{a} }$ equation (1)

Speed of the boat traveling in the lake:
$S_{l}= \frac{15}{t_{l} }$
But we know that $t_{l}=t_{a}+1$ , so:
$S_{l}= \frac{15}{t_{a}+1}$ equation (2)

Solving for $t_{a}$ in equation (1):
$S_{l}-2= \frac{6}{t_{a} }$
$t_{a}= \frac{6}{S_{l}-2}$ equation (3)

Solving for $t_{a}$ in equation (2):
$S_{l}= \frac{15}{t_{a}+1}$
$t_{a}+1= \frac{15}{S_{l}}$
$t_{a}=\frac{15}{S_{l}}-1$
$t_{a}= \frac{15-S_{l}}{S_{l}}$ equation (4)

Replacing equation (4) in equation (3):
$t_{a}= \frac{6}{S_{l}-2}$
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$

Solving for $S_{l}$ :
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$
$(15-S_{l})(S_{l}-2)=6S_{l}$
$15S_{l}-30-S_{l}^2+2S_{l}=6S_{l}$
$S_{l}^2-11S_{l}+30=0$
$(S_{l}-6)(S_{l}-5)=0$
$S_{l}=6$ or $S_{l}=5$

We can conclude that the speed of the boat traveling in the lake was either 6 km/hour or 5 km/hour.

3 0

4 years ago

Which set of steps can be used to prove the sine sum identity, sin(x + y) = sin(x)cos(y) + cos(x)sin(y)? Use the complementary r

Vilka [71]

Answer:

[A] use the complementary relationship between sine and cosine to rewrite sin(x + y) as cos(pi/2-(x+y)). apply the cosine sum identity. then simplify using sin(–y) = –sin(y) and cos(–y) = cos(y).

Step-by-step explanation:

i got it right

screw that other person l0l

note that sin(-x)=-sin(x) and cos(-x)=cos(x)

so sin(-y)=-sin(y) and cos(-y)=cos(y)

or something like that idfk

7 0

3 years ago

CAN SOMEONE PELSE HELP ME!!!!!!!!!!!11

GuDViN [60]

Answer:

It's false.

Step-by-step explanation:

Dont ask me! all i know is that no.4 is false and that I learned bar lines and negitives in 5th grade!!

3 0

3 years ago

WILL MARK BRAINLIEST!!!! Which highlighted word in the passage has connotations that create a calm tone?

vladimir2022 [97]

The answer is A) Napping

7 0

3 years ago

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