solve

X= 1000 copies

Second,

Sell a Momo with 8/5 big peaches.

Then Momo =5 1÷(0.2+0.3*8/5)=75.

Similarly, sell a big peach with 5/8 Momo.

So big peach = 51÷ (0.3+0.2 * 5/8) =120.