Metal rod A is 0.300 m long expands by 6.50x10^-4 m when its temperature is increased by 100 degrees Celsius. Another rod made of different metal B and of the same length expands by 3.50x10^-4 m for the same increase in temperature. A third rod C, also 0.300 m long, is made up of pieces of the first two metals placed end-to-end and expands 5.80x10^4 m for the same increase in temperature. Find the length of each portion of the third bar. i have no idea to solve this.. help..