A 130 lbs man burned 194 calories during a 30 minute tennis session. How many calories would a 250 lbs man burn in the same time frame doing the same activity(assuming they burn calories at the same rate)?

I just need help figuring out what the equation is, I can't seem to get it right....

Assuming the the burning of calories is in a direct proportion to the mass of the person doing the exercise, and since the time frame is the same,

130/194 = 250/x
130x = 48500
x = appr 373 cal's