contestada

Seven years ago, Grogg's dad was $9$ times as old as Grogg. Four years ago, Grogg's dad was $6$ times as old as Grogg. How old is Grogg's dad currently?

Respuesta :

To find Grogg's dad's current age, let's use algebraic equations to solve the problem.

Let's start by assigning variables. Let G represent Grogg's current age, and let D represent Grogg's dad's current age.

From the first sentence, we know that 7 years ago, Grogg's dad was 9 times as old as Grogg. We can express this as an equation:

\[D - 7 = 9(G - 7)\]

From the second sentence, we know that 4 years ago, Grogg's dad was 6 times as old as Grogg. We can express this as another equation:

\[D - 4 = 6(G - 4)\]

Now, we can solve these two equations to find the values of G and D.

Let's start with the first equation:

\[D - 7 = 9(G - 7)\]

Distributing 9 to (G - 7) gives us:

\[D - 7 = 9G - 63\]

Simplifying further, we have:

\[D = 9G - 63 + 7\]

\[D = 9G - 56\]

Now, let's look at the second equation:

\[D - 4 = 6(G - 4)\]

Distributing 6 to (G - 4) gives us:

\[D - 4 = 6G - 24\]

Simplifying further, we have:

\[D = 6G - 24 + 4\]

\[D = 6G - 20\]

Now, we have two equations for D:

\[D = 9G - 56\]

\[D = 6G - 20\]

Since both equations represent the same value, we can equate them:

\[9G - 56 = 6G - 20\]

Simplifying, we have:

\[3G = 36\]

\[G = 12\]

Now that we know Grogg's age is 12, we can substitute this value back into one of the original equations to find D.

Let's use the equation:

\[D = 9G - 56\]

Substituting G = 12, we have:

\[D = 9(12) - 56\]

\[D = 108 - 56\]

\[D = 52\]

Therefore, Grogg's dad is currently 52 years old.

In summary:

- Grogg is currently 12 years old.

- Grogg's dad is currently 52 years old.