In this question why is the second stmnt not sufficient in itself?

Please correct me- the second stmnt says the sum of negative numbers is 10.6 less than the sum of positive numbers which means:

The sum of negative numbers will always be negative right? for example -2+(-3)+(-6)=-11 so wudnt it imply the x-(-y)=x+y (wherein x is the sum of positive numbers and y is the sum of negative numbers. And the second statement gives us the difference between the sums of negative and positive numbers thereby we get the equation= x-(-y)=10.86