Could you please explain the logic behind this?

Question 4 1 / 1 pts Decompose the return an American would have if he had bought a German stock at 100 per share and sold it one year later at 120. The spot exchange rate one year ago was $1.50 = 1 and the spot rate prevailing at the end of the year was $1.55 = 1. 24% total return; 20% asset return; 4% attributable to exchange rate changes 20% total return; 16.77% asset return; 3.23% attributable to exchange rate changes 24% total return; 20% asset return; 3.33% attributable to exchange rate changes None of the above