The highest score will be the greatest sum of the two players
So let us find the sum of each round
The team score for 1st round = 2 + 10 = 12
The team score for 2nd round = -5 + -15 = -20
the team score for 3rd round = -5 + 2 = -3
The team score for 4th round = 8 + -4 = 4
(-v) means lost (+) means win, then
The highest score in the 1st round