There are two 74193s. The lower one represents the units, and its outputs represent 1, 2, 4 and 8. The upper one represents tens and its outputs represent 10, 20, 40 and 80. I labeled the diagram using that convention. The lower counter is reset whenever the outputs representing 8 and 2 both go high, which is when is shows 10, so it will only show 10 for a few microseconds before showing 0.
When the total count gets to 24, both counters are reset.
I realise that if you are counting 0 - 24, the upper counter never gets beyond 20, so the two outputs representing 40 and 80 should never operate.