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barxatty [35]
2 years ago
7

3. A train travels 20 km at a uniform speed of 60 km/h and the next 20 km at a uniform speed of 80km/h. Calculate its average sp

eed.​
Mathematics
1 answer:
34kurt2 years ago
3 0

Answer:

Given,

Distance traveled = 20 km

Speed = 60 km/h

So, timetaken=DistanceSpeed=2060=13h

For the next journey

Distance traveled = 20 km

Speed = 80 km/h

So, timetaken=DistanceSpeed=2080=14h

Now,

Total distance traveled = 20 + 20 = 40 km

Total time taken = 13+14=712

We know,

Averagespeed=TotaldistancetraveledTotaltimetaken=40712=68.5 km/h

Hence the average speed of the train is 68.5 km/h

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Use the parabola tool to graph the quadratic function f(x)=x^2+10x+24.
GuDViN [60]
Hello there!

Today we are just going to graph this quadratic function.

First let's find the vertex. There are two ways to find the vertex, but we will use the formula -b/2a today!

f(x)=x^2+10x+24

plug this into -b/2a where a=1 and b=10. (I found out what a and b equal by looking at the each term's coefficient.)

-10/2(1)
-10/2
-5

So the x value for our vertex is -5, so now to find the y-value, we need to plug in -5 in place of x in the equation...
f(x)=x^2+10x+24
f(-5)=(-5)^2+10(-5)+24
f(-5)=25-50+24
f(-5)=-25+24
f(-5)=-1

So the vertex is at (-5,-1)
Look at the table...
X] -5
Y] -1

Now we need to plug in number around the vertex to the equation.
X] -3 -4 -5 -6 -7
Y] -1

f(x)=x^2+10x+24
f(-4)=(-4)^2+10(-4)+24
f(-4)=16-40+24
f(-4)=-24+24
f(-4)=0

f(-3)=(-3)^2+10(-3)+24
f(-4)=9-30+24
f(-4)=-21+24
f(-4)=3

X] -3 -4 -5 -6 -7
Y] 3 0 -1

Now because the parabola is symmetrical, we don't have to plug in the other points to the equation. Watch what I do...
X] -3 -4 -5 -6 -7
Y] 3 0 -1 0 3


I really hope this helps!
Best wishes :)

8 0
4 years ago
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Answer:

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3 years ago
write the expression for the perimeter of rectangle with a length that is 4 centimeters longer than three times it's width.
Rina8888 [55]
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IRINA_888 [86]

Answer:

\frac{-215}{30}

Step-by-step explanation:

Given-2\frac{9}{10} \ and\ -5\frac{4}{15}

on solving this mixed fraction we get;

-\frac{29}{10}\ and\ -\frac{64}{15}

Now adding these fractions by same denominator method.

-\frac{29\times3}{10\times3} +[-\frac{64\times2}{15\times2} ]\-\frac{87}{30} +[-\frac{128}{30}]\ = -\frac{215}{30}

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