Answer:
Mimi is 15.
Step-by-step explanation:
Set up two equations, and solve by elimination.
2(m+5) = d+5
- 3(m-5) = d-5
_____________
2(m+5) - 3(m-5) = 10
2m + 10 - 3m + 15 = 10
-m + 25 = 10
-m = -15
<u>m = 15</u>
Plug this back in to get dad's age.
2(m+5) = d+5
2(15+5) = d + 5
2(20) = d + 5
40 = d + 5
<u>d = 35</u>
<u></u>
Answer:
10 and 15
Step-by-step explanation:
Let 'x' and 'y' are the numbers we need to find.
x + y = 25 (two numbers whose sum is 25)
(1/x) + (1/y) = 1/6 (the sum of whose reciprocals is 1/6)
The solutions of the this system of equations are the numbers we need to find.
x = 25 - y
1/(25 - y) + 1/y = 1/6 multiply both sides by 6(25-y)y
6y + 6(25-y) = (25-y)y
6y + 150 - 6y = 25y - (y^2)
y^2 - 25y + 150 = 0 quadratic equation has 2 solutions
y1 = 15
y2 = 10
Thus we have
:
First solution: for y = 15, x = 25 - 15 = 10
Second solution: for y = 10, x = 25 - 10 = 15
The first and the second solution are in fact the same one solution we are looking for: the two numbers are 10 and 15 (since the combination 10 and 15 is the same as 15 and 10).
