I don't know how they got the 1.023955. Can someone clarify please? Please refer to the info below:

$4,900,000Kamada: CIA Japan (A).Takeshi Kamada, a foreign exchange trader at Credit Suisse (Tokyo), is exploring covered interest arbitrage possibilities. He wants to invest

or its yen equivalent, in a covered interest arbitrage between U.S. dollars and Japanese yen. He faced the following exchange rate and interest rate quotes. Is CIA profit possible? If so, how?

Arbitrage funds available	$	4,900,000
Spot rate (/$)		118.48
180-day forward rate (/$)		117.74
180-day U.S. dollar interest rate		4.791	%
180-day Japanese yen interest rate		3.393	%

U.S. dollars = U.S. dollars (1+U.S. dollar interest rate 180 days) ) in 180 days U.S. dollars in 180 days = $4,900,000 x 1.023955 = $5,017,379.50