We have the equation of the line as follows:
y = 0.5x + 79
We want to calculate the melting point (the y value) of DNA with 50% gc content (the x value).
The gc content represents the value of x in the equation, so to calculate the melting point (y), we will simply substitute the x with 50 in the equation of the line as follows:
melting point = 0.5(50) + 79 = 25 + 79 = 104 degrees
6*45=270 is the first step you should do to get the answer you are looking for. The next thing I would do is go to all the answers to see which one comes out the same way. The first one comes to be 246, the next one is 54, the next is 270 and the last one is 220. 6*40+6*5 is the correct answer.
