Two brothers are respectively 6 and 9 yrs old. in how many years will the ratio of their ages be 4:5?
To find out the number of years it will take for the ratio of the brothers' ages to be 4:5, we can set up an equation.
Let x represent the number of years we want to find.
Currently, the ratio of their ages is 6:9, which simplifies to 2:3.
After x years, the older brother's age will be 9 + x, and the younger brother's age will be 6 + x.
We want to find a value of x that will make the ratio of their ages 4:5, or 4/5.
Setting up the equation:
(9 + x) / (6 + x) = 4/5
To solve this equation, we can cross-multiply:
(9 + x) * 5 = (6 + x) * 4
Simplifying:
45 + 5x = 24 + 4x
Subtracting 4x from both sides:
x = 24 - 45
x = -21
The result is -21, which means that in -21 years, the ratio of their ages will be 4:5. However, since time cannot be negative, it means that the ratio of their ages will never be 4:5.
Let y be the number of years from today. So you know that:
(6 + y) / (9 + y) = 4 / 5
Can you solve from here?