Acolony of ants carried away 10 of your muffins. that was 2/5 of all of them! how many are left?

2/5=0.4=40%
If 40%=10 muffins, then 20 muffins=80%
100%-80%=20%
We know that 40%=10 muffin, so 20% out of 10 muffins will be 5.
If 25 muffins was at the beginning, and a colony of ants carried away 10 of them, then 15 muffins are left.

I’m not absolutely sure but i think it’s 7x6x5x4x3x2=5040 because as the first character you can take any of the 7 given then you are left with 5 then 6 then 4 etc.