Your answer would be 1, or 72+25.
What is happening in this case is a negative number is being subtracted from a positive. This means you are taking away a negative. The two negatives cancel each other out, and then it becomes you are adding a positive.
Another way I like to think about this is the two minus symbols combine together to form a plus sign.
Hope this helped!
What a clever sneaky little problem !
There can only be two of them: 1221 and 2112 .
Train A weighs 181 tons and train B weighs 70 tons.
(xA+xB)/2, (yA+yB)/2 = (4,3)
(xA+xB)/2 = 4
(-2+xB) = 8 --> xB = 8+2 --> xB = 10
(yA+yB)/2 = 3
(6+yB) = 6 --> yB = 6-6 --> yB = 0
B = (10,0)
