first you set up a proportion:
7% = 7 / 100
7 x
----- = --------
100 45.50
then cross multiply:
100x = 7 ( 45.50 )
multiply:
100x = 318.5
then divide:
100x 318.5
------- = -------
100 100
x = 3.185
then add x to original price:
45.50 + 3.185 = 48.685
round to hundredths:
48.69 is your answer