Mathematics: Find r 25= r•r•8 hurry go fast please

Find r 25= r•r•8 hurry go fast please

7obadiah

19.01.2022

$r = \frac{5}{2\sqrt{2} } \\r = -\frac{5}{2\sqrt{2}}$

Step-by-step explanation:

25= r•r•8 ⇔ 25/8 = r²

then

$r^{2} =(\frac{5}{2\sqrt{2} } )^{2} \\\\Then\\\\r = \frac{5}{2\sqrt{2} } \\Or\\r = -\frac{5}{2\sqrt{2}}$

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isa5166

23.10.2022

The total distance he drove is 350 miles, with an average speed of 46.67 miles/hour.

Step-by-step explanation:

Let t_1 and t_2 be the time of driving at a slower rate and at a faster rate respectively.

Given that the total distance = d

The speed for the first 150 miles = 60 miles/hour.

So, $150=60\times t_1$ [ as distance = speed x time]

$\Rightarrow t_1=2.5$ hours.

The remaining distance = d-150 miles.

Speed for the remaining distance = 60 miles/hour.

As the time he spent driving at the faster speed was twice the time he spent driving at the slower speed,

So, the time of driving at a faster rate, $t_2 = 2t_1=2\times2.5=5$ hours

So, $d-150=60\times t_2$ [ as distance = speed x time]

$\Rightarrow d-150=20\times 5=100$

$\Rightarrow d = 100+150=350$ miles.

The average speed of the journey = (Total distance)/(Total time taken )

=d/(t_1+t_2)

=350/(2.5+5)

=350/7.5

=46.67 miles/hour.

Hence, the total distance he drove is 350 miles, with an average speed of 46.67 miles/hour.

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