So, I didn't quite understand your question clearly, but I'll try my best to answer it.
So, the first question is quite simple: Did the runner have a % decrease in his time or an increase.
Well, 7:45 is minor than 5:51. So, his time decreased.
2nd question:
The percent of change. Well, first things first 7:45 has 2 different units, wich are minutes and seconds, I suppose. Same goes for 5:51.
So let's put everything in seconds. multiply both the 7 and 5 for 60(for every minute has 60 seconds.)
That means:
7*60= 420+45 = 465.
5*60=300+51=351.
Now, let's do the math itself:
465 -> 100%
351 -> x%
Is equal to about 75,5%
How much did it decrease then?
(75,5-100)%= 24,5%, approximately
Answer:
4.5045045 x 10^44
Step-by-step explanation:
I just put it into a calculator idk if its even right
Correct answer is: distance from D to AB is 6cm
Solution:-
Let us assume E is the altitude drawn from D to AB.
Given that m∠ACB=120° and ABC is isosceles which means
m∠ABC=m∠BAC = 
And AC= BC
Let AC=BC=x
Then from ΔACD , cos(∠ACD) = 
Since DCB is a straight line m∠ACD+m∠ACB =180
m∠ACD = 180-m∠ACB = 60
Hence 

Now let us consider ΔBDE, sin(∠DBE) = 

9514 1404 393
Answer:
a. x + 4y = 160
b. 160
c. 40
Step-by-step explanation:
a. We can define the variables as ...
x = number of 1/2-liter bottles
y = number of 2-liter bottles
For the total number of liters to be 80, we require
1/2x + 2y = 80
We can multiply this by 2 to eliminate the fraction.
x + 4y = 160
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b. The x-intercept is 160. It is the number of 1/2-liter bottles required when no 2-liter bottles are used.
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c. The y-intercept is 40. It is the number of 2-liter bottles required when no 1/2-liter bottles are used.