Ken has $20 less than John. Leo has $15 less than Ken. Work down the chain.

John$45Ken?$20Leo?$15

Plain numbers are given; italic underlined numbers are worked out.

  1. Ken → $45 − $20 = $25
  2. Leo → $25 − $15 = $10

Leo has $10.

Check: Leo $10 + $15 = Ken $25; Ken $25 + $20 = John $45. ✓