Argentina is clearly the larger of the two: about 2,782,703 km² km² against 1,863,027 km² km², roughly 1.5× at true size. Drag one onto the other on the map above to feel the gap.
Argentina sits in South America, Sudan in Africa. On the old Mercator map the latitude gap distorted how large each felt beside the other; at true size the answer is simply 1.5×.
The old map muddied it further: Mercator inflates Argentina about 1.5× and Sudan about 1.1×, so on a Mercator-style map this pair appears 2× apart instead of the true 1.5×.
Sudan fits 1× into Argentina.