Question

2 balls are rolling towards each other from the opposite ends of a straight tube that is

Answer 1

Answer:

6 seconds

Step-by-step explanation:

In second 1, the distance that separates them is  80 cm

Then, in second 2, it is an additional 76 cm which is 156

then 72, etc. etc.

From that, we can continue adding until we the total sum is 420.

80+76+72+68+64+60=420

That's 6 seconds

Not the most elegant solution but I think one of the simplest.

Answer 2

6 seconds!!!!!!!!!!!! that should be the answer