The answer is 4 groups because 21+7=28,28÷4=7,and 7×4=28
If two lines intersect, and intersect only at one point, then the coordinates of that point satisfy the equations of the lines.
If, on the other hand, one line coincides with the other, then there are an infinite number of solutions.
This problem is really simple as you would plug in what's given to you.
So g would be 1.2, so you would subtract 1.6 - 1.2
Your answer would be 0.4
X=first train speed
y=second train speed
sum of speeds is 725.2
x+y=725.2
x is 10.8 more than y
x=10.8+y
subsitute 10.8+y for x
10.8+y+y=725.2
10.8+2y=725.2
minus 10.8 from both sides
2y=714.4
divide both sides by 2
y=357.2
x=10.8+y
x=10.8+375.2
x=386
the speed of first train is 386mph
second train is 357.2mph
