The diagram shows that
AB = 5
AC = AB+BC = 5+2 = 7
DE = 7
DF = DE+EF = 7+x
So,
AB/AC = DE/DF
5/7 = 7/(7+x)
5(7+x) = 7*7
5(7+x) = 49
35+5x = 49
5x = 49-35
5x = 14
x = 14/5
So EF = 14/5 in fraction form
In decimal form, EF = 2.8 (since 14/5 = 2.8)
The half-life for such a substance is the time required to have the amount (in grams ) at time (in seconds ), , decay to half the starting amount . In other words, for krypton-91, after 10 seconds we would have . We can use this information to solve for , then plug in various values of to find the amount of krypton-91 that's left...
But we don't need to! We already know it takes 10 seconds for half of the substance to decay. So if we start with 16 grams, then after 10 seconds, 8 grams will remain.
10s later (after a total of 20 seconds), 4g will remain.
10s later (30s), 2g will remain.
10s later (40s), 1g will remain.
10s later (50s), 1/2 g will remain.
Answer:
10 one-dollar and 4 five-dollar bills.
Step-by-step explanation:
Let x = the number of one-dollar bills and y = number of five-dollar bills.
Then:
x + y = 14
x + 5y = 30 (using the values of the bills)
Subtracting the 2 equations:-
-4y = -16
y = 4
so x + 4 = 14
x = 10.
There are 10 one-dollar bills and 4 five-dollar bills.
58
First solve what is inside the parentheses (PEMDAS)
(5-21)+(-7+81)
(-16)+(74)
Add
58
Hope this helps! :)
Answer:
0.4
Step-by-step explanation:
$4.80 divided by 12 = 0.4