Question 262365
Since both the Mazda and Honda depend on the Nissan, let's name a variable for the Nissan's weight, N.  Since the Mazda weighs 20 pounds more, then it weighs N+20.  Since the Honda weighs 70 pounds more, it weighs N+70.  So since all together they weigh 10,050, we have that

Nissan + Mazda + Honda = 10,050

N + (N+20) + (N+70) = 10,050
3N + 90 = 10,050
3N = 9,960
N = 3,320

So the Nissan weighs 3,320 lbs.  Since the Mazda is 20 more, the Mazda weighs 3,340 lbs, and since the Honda is 70 lbs more, the Honda weighs 3,390 lbs.