Using single-period arithmetic returns, calculate the value after two periods for the realized returns of these two portfolios:

(Portfolio A) $100 invested, realizing a period with a 10% gain, followed by another period with a 10% gain ("average" 10% per period gain)

(Portfolio B) $100 invested, realizing a period with a 50% gain, but followed by a period with a 25% loss ("average" 12.5% per period gain)

What is the difference in dollars after these two periods (Portfolio A value minus Portfolio B value)?