There are 4! = 24 poosible permutations of the four letters. Let the letters be A, B, C and D. Two permutations will have only letter A in the correct envelope, two more permutations will have only letter B in the correct envelope, two more will have only letter C in the correct envelope and two more will have only letter D in the correct envelope. Therefore 8 out of the 24 possible permutations will have only one letter with the correct address. The required probability is 8/24 = 1/3.
1. 3x+1=4/5(4x)
15x+5=4(4x)
16x=15x+5
x=5
2. 13x3=39
13x2=26
x=27
x=27
To find the number of half lives divide the total number of days by the number of days for 1 half live:
1104 / 138 = 8
There are 8 half lives.
To find the total amount left multiply the starting amount by 1/2 to the 8th power:
38 * 0.5^8 = 0.148 = 0.15 grams
The answer is the last one.
Answer:
y = 4;
y = 7;
x = 6
Step-by-step explanation:
Given the rule, y = x/2, find the missing values as shown below:
✔️For the first row, to find y, substitute x = 8 into y = x/2,
y = 8/2
y = 4
✔️For the second row, to find y, substitute x = 14 into y = x/2,
y = 14/2
y = 7
✔️For the third row, to find x, substitute y = 3 into y = x/2,
3 = x/2
3*2 = x
6 = x
x = 6
<h2>the original number is 38</h2>
Step-by-step explanation:
Let the two-digit number be 10t+u where t is the tens digit and u the units digit.
-------------------
EQUATION:
t+u = 11
10u+t = 10t+u + 45
-------------
Rearrange the equations:
t+u = 11
9t-9u = -45
-------------
Simplify:
t+u = 11
t-u = -5
---------
Add the equations to solve for "t":
2t = 6
t = 3
--------
Substitute to solve for "u":
3+u = 11
u = 8
