Bill is 1 unit ($4150). His sister has 4 times as much, so 4 units. Altogether that is 5 units.

Bill$4150Sister$4150$4150$4150$4150total = ?

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

  1. Sister = 4 units → 4 × $4150 = $16600
  2. Total = 5 units → $4150 + $16600 = $20750

Together they have $20750.

Check: $4150 + $16600 = $20750. ✓