We want to select 3 pairs of people from a group of 6.
We use the formula:
n! / (r! * (n -r)!)
where n = 6 and r = 2
combinations = 6! / (2! * 4!) =
combinations = 6 * 5 / 2
combinations = 15
Source:
1728.com/combinat.htm
Answer:
It will take 13.58 minutes until there are 80 grams of the element remaining
Step-by-step explanation:
An element with a mass of 990 grams decays by 16.9% per minute.
We are supposed to find how long will it be until there are 80 grams of the element remaining
Formula :
N(t)=Amount after t minutes
=Initial amount
r = rate of decrease = 0.169
t = time in minutes
Substitute the values in the formula :


t=13.58
Hence It will take 13.58 minutes until there are 80 grams of the element remaining
Answer:5X+2=4X-9\quad :\quad X=-11
Step-by-step explanation:
5X+2=4X-9
5X+2-2=4X-9-2
5X=4X-11
5X-4X=4X-11-4X
X=-11
Answer:
12 is composite because it has more than two factors.
Step-by-step explanation:
Answer:
(5h-4t)(5h+4t)
Step-by-step explanation:
25h² - 16t²
adding and subtracting 20ht from it (√25 and √16 = 5x4 = 20):
25h² + 20ht - 20ht -16t²
factor:
(5h-4t)(5h+4t)