16 cupcakes is the answer
Parallel lines have the same slope, so Line Q should also have an undefined slope
Every six days he'd drink 1,050 liters because
350 liters every 2 days -
350 x 2 = 700
700 liters every 4 days -
2 x 3 = 6
1,050 liters every 6 days.
Hope this helps.