Question

2 balls are rolling towards each other from the opposite ends of a straight tube that is
420 cm long. Ball A travels 50 cm while ball B travels 30 cm in the 1st second. Both
balls travel 2 cm less than the previous distance in each subsequent second. How long
does it take for the two balls to meet?

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