Abundled computer package costs $760.50 there is an 8% convenience fee for assembling the package how much will the computer cost with assembly?

I'm confused on this could anyone me and show me what i need to do to solve it.

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

Which answer goes into the box? (90° clockwise rotation, 90° counter clockwise rotation, translation, or glide reflection)