WordGPT

A parent is 4 times as old as their child. Together they are 90. How old is each?

The child is 18 and the parent is 72.

Explain it step by step in chatMake a short video of it

How to work it out

  1. 1

    Let x be the child's age. The parent is 4 times as old, so the parent is 4x.

  2. 2

    Together they are 90:

    x+4x=90x + 4x = 90
  3. 3

    Combine the x terms and divide:

    5x=90 ⇒ x=905=185x = 90\ \Rightarrow\ x = \frac{90}{5} = 18
  4. 4

    The parent is 4 × 18 = 72.

  5. 5

    Check: 18 + 72 = 90 ✓ and 72 = 4 × 18 ✓.

LaTeX source of the formulas on this page
\[ x + 4x = 90\ \Rightarrow\ x = 18 \]
\[ x + 4x = 90 \]
\[ 5x = 90\ \Rightarrow\ x = \frac{90}{5} = 18 \]

Questions

How old is the child?

18.

How old is the parent?

72.

Similar problems

    Parent is 4 times the child's age, total 90: 72 and 18 | WordGPT