Hello help?

Agrocery store has 12 lb of trail mix that is 10% banana chips. the store's manager would like to add banana chips to bring the new mix up to 25% banana chips. write and solve a system of equations to find out how many pounds of banana chips manager needs to add.

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

What is the base of 1/9 to the power of 2