You need some specific information. How much did all 3 parts cost? What do you know about the steering and the radio?
You know the total cost of all 3 parts. You also know how much the radio cost. You can figure out what the steering cost. What’s left is the cost of the Gruber Chip.
Sonja a lot spent less money on the Gruber Chip than on the whole system. How much did she spend just on the Gruber Chip?