Answer: 2500 years
Step-by-step explanation:
I'm not quite sure if I'm doing this right myself but I'll give it a shot.
We use this formula to find half-life but we can just plug in the numbers we know to find <em>t</em>.
We know half-life is 5730 years and that the parchment has retained 74% of its Carbon-14. For 
let's just assume that there are 100 original atoms of Carbon-14 and for A(t) let's assume there are 74 Carbon-14 atoms AFTER the amount of time has passed. That way, 74% of the C-14 still remains as 74/100 is 74%. Not quite sure how to explain it but I hope you get it. <em>h</em> is the last variable we need to know and it's just the half-life, which has been given to us already, 5730 years, so now we have this.
Now, solve. First, divide by 100.
Take the log of everything
Divide the entire equation by log (0.5) and multiply the entire equation by 5730 to isolate the <em>t</em> and get
Use your calculator to solve that giant mess for <em>t </em>and you'll get that <em>t</em> is roughly 2489.128182 years. Round that to the nearest hundred years, and you'll find the hopefully correct answer is 2500 years.
Really hope that all the equations that I wrote came out good and that that's right, this is definitely the longest answer I've ever written.
Answer:
A salad costs $2.50
A sandwich costs $4.50
A drink costs $1.25
Step-by-step explanation:
Let x represent the salad, y represent the sandwich, and z represent the drink.
Since three salads, two sandwiches, and one drink cost $17.75:
3x + 2y + z = 17.75 (1)
Since one salad, one sandwich, and three drinks cost $10.75:
x + y + 3z = 10.75 (2)
Since a salad costs twice as much as a drink:
x = 2z (3)
Multiply the equation 2 by -2 then, sum the equation 1 and equation 2:
-2x - 2y - 6z = -21.50
3x + 2y + z = 17.75
→ x - 5z = -3.75
Replace the x with 2z using equation 3:
2z - 5z = -3.75
-3z = -3.75
z = 1.25
x = 2z → x = 2.50
x + y + 3z = 10.75 → 2.50 + y + 3.75 = 10.75 → y + 6.25 = 10.75 → y = 4.50
Answer:
8
Step-by-step explanation:
2x2 is 4 and x 2 is 8. I think im right?
Answer:
8-3=8-3
Step-by-step explanation:
You want to find the monthly average over the past 6 months.
July: $78.56
August: $30.21
September: $81.20
October: $79.08
November: $66.18
December: $100.75
Add all of these up
(July) $78.56
(August) $30.21
(September) $81.20
(October) $79.08
(November) $66.18
(December) + $100.75
----------------------------------------------
(Total cost) $435.88
There are 6 months you are calculating for, therefore divide the total (combined) cost of 6 months with the total number of months (in this case, 6)
$435.88 (total cost of 6 months) ÷ 6 (months)
The average cost per month of over the past 6 months is $72.66.
