Hello!
First of all, we have a 4/52, or 1/13 chance of selecting a pair. Then, we select 1/3 cards 3 times, so we use this as our other fraction.
=
Therefore, we have a 1/39 or about 3%.
I hope this helps!
Complete question :
Sam knows that his MP3 player has 40% of its battery life left and that the battery
charges by an additional 12 percentage points every 15 minutes. What percent of
the mp3's battery will be charged when Sam and his family leave? If mp3 was plugged in an hour before his family plan to leave.
Answer:
88%
Step-by-step explanation:
Time before leaving = 1hour
Current percentage = 40%
Charge rate = 12% every 15 minutes
Therefore,
Charge rate per minute :
12% / 15 = 0.8% per minute
Charge recieved after one hour (60 minutes) :
0.8% * 60
= 48%
Therefore, total charge after just before leaving is:
Current percentage + percentage received
40% + 48%
= 88%
Yes seth your answers are all corret i seen them i did that paper too
Both factors are negative so the result would be positive. C. Is the answer
Answer:
1.) 8.09g ; 2) 206.7 years
Step-by-step explanation:
Given the following :
Half-life(t1/2) of Uranium-232 = 68.9 years
a) If you have a 100 gram sample, how much would be left after 250 years?
Initial quantity (No) = 100g
Time elapsed (t) = 250 years
Find the quantity of substance remaining (N(t))
Recall :
N(t) = No(0.5)^(t/t1/2)
N(250) = 100(0.5)^(250/68.9)
N(250) = 100(0.5)^3.6284470
N(250) = 100 × 0.0808590
= 8.0859045
= 8.09g
2) If you have a 100 gram sample, how long would it take for there to be 12.5 grams remaining?
Using the relation :
N / No = (1/2)^n
Where N = Amount of remaining or left
No = Original quantity
n = number of half-lifes
N = 12.5g ; No = 100g
12.5 / 100 = (1/2)^n
0.125 = (1/2)^n
Converting 0.125 to fraction
(1/8) = 1/2^n
8 = 2^n
2^3 = 2^n
n = 3
Recall ;
Number of half life's (n) = t / t1/2
t = time elapsed ; t1/2 = half life
3 = t / 68.9
t = 3 × 68.9
t = 206.7 years
