Answer:
21 and 22
Step-by-step explanation:
Let's work backward from that 81%: x/25 = 0.81 yields x = 20.25. Nominally, 20.25 / 25 = 0.81, but x must be an integer. Let's round 20.25 off to 20.
Thus, if Kalsom got 81%, it was a result of his having done 20 questions correctly.
81% corresponds to 20 questions correct;
82% to 20.5 questions correct, or, rounding up, to 21 questions correct;
83% to 20.75, or 21;
84% to 21 questions correct; this is the only result that makes sense (whole number of questions answered correctly)
85% to 21.25;
86% to 21.5;
87% to 21.75;
88% to 22 questions correct (this makes sense, unlike the last three)
89% to 22.25;
90% to 22.5;
91% to 22.75;
Assuming that the number of questions correct MUST be integer, then the possible number correct are 21 and 22, corresponding to 84% and 88% respectively.
<span>As the age of the U-235 sample is 2.631 billion years, and the half-life of U-235 is 713 million years, the sample has undergone 2.361 X 1,000,000,000 / 713 X 1,000,000 = 3.69 half lives. In each half-life the sample reduces to half its original weight according to the radioactive Half-Life Formula:
ln (Nt /N0) = -kt, where N0 = mass of the original weight of radioactive material, Nt = mass of radioactive material at time t, k = decay constant and t = time interval . We have to put Nt/N0 = 1/2 for time interval = half-life.</span>
Answer:
y = 65
Step-by-step explanation:
45 + 57 = x + y
x = 37
45 + 57 = 37 + y
45 + 57 = 102
102 = 37 + y
102 = 37 + y
-37 -37
102 - 37 = 65
37 + y - 37 = y
65 = y
y = 65
Answer:
4x + 5y = 20
Step-by-step explanation:
4x + 5y = 20
5y = -4x + 20 (Subtract 4x to isolate 5y. Put the 4x in front of the 20)
y = 
+ 4 (Divide all by 5 to isolate y)
And then it's done and in slope-intercept form
or 
is greater than -1 but less than 0
I hope this helped :)
To solve this, you would divide 478 by 18, which equals 26.5555556. Since you can't have half a package of paper, the answer would be 26. Hope this helps!
