A parent is 4 times as old as their child. Together they are 30. How old is each?
The child is 6 and the parent is 24.
How to work it out
- 1
Let x be the child's age. The parent is 4 times as old, so the parent is 4x.
- 2
Together they are 30:
- 3
Combine the x terms and divide:
- 4
The parent is 4 × 6 = 24.
- 5
Check: 6 + 24 = 30 ✓ and 24 = 4 × 6 ✓.
LaTeX source of the formulas on this page
\[ x + 4x = 30\ \Rightarrow\ x = 6 \]
\[ x + 4x = 30 \]
\[ 5x = 30\ \Rightarrow\ x = \frac{30}{5} = 6 \]Questions
How old is the child?
6.
How old is the parent?
24.