Question
judy is now twice as old as adam, but six years ago, she was 5 times as old as he was. how old is judy now?
Answers
Answered by
GPT-4o mini
Let's denote Judy's current age as \( J \) and Adam's current age as \( A \).
From the problem, we have two pieces of information:
1. Judy is now twice as old as Adam:
\[
J = 2A
\]
2. Six years ago, Judy was 5 times as old as Adam:
\[
J - 6 = 5(A - 6)
\]
Now, let's solve these equations step-by-step.
First, substitute the expression for \( J \) from the first equation into the second equation:
\[
2A - 6 = 5(A - 6)
\]
Now, expand the right side:
\[
2A - 6 = 5A - 30
\]
Next, rearranging the equation gives:
\[
2A - 5A = -30 + 6
\]
\[
-3A = -24
\]
\[
A = 8
\]
Now that we know Adam's age, we can find Judy's age using the first equation:
\[
J = 2A = 2 \times 8 = 16
\]
Thus, Judy is currently **16 years old**.
To verify our solution, let's check the second condition:
- Six years ago, Judy's age was \( 16 - 6 = 10 \) and Adam's age was \( 8 - 6 = 2 \).
- Indeed, six years ago, Judy was \( 10 \) years old, which is \( 5 \times 2 \) (Adam's age at that time).
Everything checks out, confirming that Judy is **16 years old** now.
From the problem, we have two pieces of information:
1. Judy is now twice as old as Adam:
\[
J = 2A
\]
2. Six years ago, Judy was 5 times as old as Adam:
\[
J - 6 = 5(A - 6)
\]
Now, let's solve these equations step-by-step.
First, substitute the expression for \( J \) from the first equation into the second equation:
\[
2A - 6 = 5(A - 6)
\]
Now, expand the right side:
\[
2A - 6 = 5A - 30
\]
Next, rearranging the equation gives:
\[
2A - 5A = -30 + 6
\]
\[
-3A = -24
\]
\[
A = 8
\]
Now that we know Adam's age, we can find Judy's age using the first equation:
\[
J = 2A = 2 \times 8 = 16
\]
Thus, Judy is currently **16 years old**.
To verify our solution, let's check the second condition:
- Six years ago, Judy's age was \( 16 - 6 = 10 \) and Adam's age was \( 8 - 6 = 2 \).
- Indeed, six years ago, Judy was \( 10 \) years old, which is \( 5 \times 2 \) (Adam's age at that time).
Everything checks out, confirming that Judy is **16 years old** now.