A parent is 5 times as old as their child. Together they are 54. How old is each?
The child is 9 and the parent is 45.
How to work it out
- 1
Let x be the child's age. The parent is 5 times as old, so the parent is 5x.
- 2
Together they are 54:
- 3
Combine the x terms and divide:
- 4
The parent is 5 × 9 = 45.
- 5
Check: 9 + 45 = 54 ✓ and 45 = 5 × 9 ✓.
LaTeX source of the formulas on this page
\[ x + 5x = 54\ \Rightarrow\ x = 9 \]
\[ x + 5x = 54 \]
\[ 6x = 54\ \Rightarrow\ x = \frac{54}{6} = 9 \]Questions
How old is the child?
9.
How old is the parent?
45.