An item that was selling for 80.00 is reduced to 68.00 find the percent decrease in price

How do you solve a question like this?

What power can you write to represent the volume of the cube shown? write the power as an expression with a base and an exponent and then find the volume of the cube

The amount cami raised during last year’s charity walk, $45.50, is 7/10 of the amount she raised this year. which equation represents n, the number of dollars she raised this year?