Answer:
So the numbers are 12 and -3.
Step-by-step explanation:
In order to solve this problem we will attribute variables to the numbers, the first one will be "x" and the second one will be "y". From the first sentence we know that the subtraction of the two numbers is equal to 15, so we have:
x - y = 15
Then the problem states that one-third of the sum of the number is equal to one quarter of the first number, so we have:
(1/3)*(x+y) = x/4
Since we now have two equations and two variables we can solve for x and y. From the first equation we have:
y = x - 15
Using this expression for the value of y in the second equation:
(1/3)*(x + x - 15) = x/4
(1/3)*(2*x - 15) = x/4
2*x - 15 = 3*x/4
2*x - 3*x/4 = 15
(8*x - 3*x)/4 = 15
5*x/4 = 15
5*x = 60
x = 60/5 = 12
y = x - 15 = 12 - 15 = -3
So the numbers are 12 and -3.
Heres the answer attached above
Answer:
79.986
Step-by-step explanation:
Let A represent isotope ⁷⁹Br
Let B represent isotope ⁸¹Br
From the question given above, the following data were obtained:
For Isotope A (⁷⁹Br):
Mass of A = 79
Abundance of A (A%) = 50.69%
For isotope B (⁸¹Br):
Mass of B = 81
Abundance of B (B%) = 49.31%
Relative atomic mass of Br =?
The relative atomic mass (RAM) of Br can be obtained as follow:
RAM = [(Mass of A × A%) /100] + [(Mass of B × B%) /100]
= [(79 × 50.69) /100] + [(81 × 49.31) /100]
= 40.0451 + 39.9411
= 79.986 amu
Thus, the relative atomic mass of Br is 79.986
The answer is 10x^2y + 23xy - 5
