Serena Williams: ‘I would have had 30’ Slams if I didn’t have to play Venus (and she would’ve had at least 15)

The Williams sisters have won a combined 30 Grand Slam singles titles. Venus accounts for seven, but former Williams coach Rick Macci recently argued that the elder sister would have had 15 to 20 more, had it not been for Serena.
Serena agreed, but what if we ran the same