Draw a bar model: Total = $26 stays constant.
After: B = 1 unit, A = 1 unit + $20. Total = 2 units + $20 = $26.
1 unit = $3 = B after. Move from B = $11 - $3 = $8.AGS Rule Box
| Total money | = | $15 + $11 = $26 |
| 2 units | = | $26 - $20 = $6 |
| 1 unit (B after) | = | $6 / 2 = $3 |
| Move from B to A | = | $11 - $3 = $8 |
Final Answer: 8