Tony is 1 unit; Andy saved twice as much, so 2 units. Together that is 3 units = $90.

Tony1Andy11$90

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

  1. 3 units → $90
  2. 1 unit → $90 ÷ 3 = $30 (Tony)
  3. Andy = 2 units → 2 × $30 = $60

Andy saved $60 and Tony saved $30.

Check: $60 + $30 = $90, and $60 = 2 × $30. ✓