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2 years ago

HELP PLSSSSSSSSSSSSSSS i need legit answer

Mathematics

2 answers:

Slav-nsk [51]2 years ago

6 0

Answer:

i think the second

Step-by-step explanation:

rodikova [14]2 years ago

5 0

Answer:

option b

Step-by-step explanation:

edg2020

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Roberto rowed 20 miles downstream in 2.5 hours. The trip back, however, took him 5 hours. Find the rate that Roberto rows in sti

almond37 [142]

Answer:

<em>Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour</em>

Step-by-step explanation:

<u>Relative Speed</u>

When a body is moving at a constant speed v, the distance traveled in a time t is:

$d=v.t$

When Roberto rows downstream, his speed in still water is added to the speed of the water, making it easier to travel the required distance.

When Roberto rows upstream, his speed in still water is affected by the speed of the water, both are subtracted and the required distance is covered in more time.

Let's call

x = Roberto's rowing speed in still water

y = Speed of the river current

The speed when rowing downstream is x+y, thus the distance traveled is

$d=(x+y).t_1$

Where t1=2.5 hours. Substituting values:

$20=(x+y)*2.5$

Rearranging, we find the downstream equation:

$2.5x+2.5y=20\qquad[1]$

The speed when rowing upstream is x-y, and the distance traveled is

$d=(x-y).t_2$

Where t2=5 hours. Substituting values:

$20=(x-y)*5$

Rearranging, we find the upstream equation:

$5x-5y=20\qquad[2]$

Multiplying [1] by 2:

$5x+5y=40$

Adding this equation to [2]:

$10x=60$

Solving:

$x=60/10=6$

Dividing [2] by 5:

$x-y=4$

Solving for y

$y=x-4=6-4=2$

Thus, Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour

3 0

3 years ago

Solve x2 − 10x = −13.

aev [14]

Answer:

Step-by-step explanation:

First, let's rearrange the given equation into something more recognizable. If we add 13 to both sides, we now have the polynomial $x^{2}-10x+13$ . We can now use the quadratic formula to solve.

Remember that the quadratic formula is

$\frac{-b+/-\sqrt{b^{2}-4ac } }{2a}$

Substitute the numbers from the equation into the formula.

$\frac{-(-10)+/-\sqrt{(-10)^{2}-4(1)(13) } }{2(1)}$

Simplify:

$\frac{10+/-\sqrt{100-52} }{2}$

$\frac{10+/-\sqrt{48} }{2}$

Here, I'm going to assume that there was a mistype in option B because if we divide out the 2 we end up with $5+/-\sqrt{48}$ .

Hope this helps!

6 0

2 years ago

Solve:

Basile [38]

$\cfrac{25x^5+10x^2}{5x} = \cfrac{5x(5x^4+2x)}{5x} =5x^4+2x$

3 0

3 years ago

Which expression is equivalent to b^m/b^n ? A. bm-n B. bmn C. bm n D. bm+n

sergij07 [2.7K]

$\cfrac{b^m}{b^n}=b^{m-n}$

8 0

3 years ago

Read 2 more answers

Write three consecutive numbers starting with number n+1, where n is natural number. Find the sum of those numbers and prove tha

netineya [11]

Consecutive numbers differ by one, which means that if you start with a certain integer $x$ , you obtain the next integer by adding one.

So, if you start with $n+1$ , the three consecutive numbers are

$n+1,\quad (n+1)+1 = n+2,\quad (n+2)+1 = n+3$

The sum of these three numbers is

$(n+1) + (n+2) + (n+3) = 3n+6$

This number is divisible by 3 because you can write it as

$3n+6 = 3(n+2)$

Note that this is true in general: the sum of three consecutive numbers is always divisible by three, because it is three times the middle number.

5 0

3 years ago