When a second identical bulb is added in series to a circuit with a single bulb, the resistance of the circuit

Will double

Explanation:

The total resistance of a circuit with n resistors in series is equal to the sum of the individual resistances:

In this problem, we have a circuit with initially one light bulb of resistance R, so the total resistance of the circuit is:

Later, a second identical bulb (so, same resistance R) is added in series to the circuit; so applying the previous formula, we see that the new total resistance is

So, the resistance has doubled.

the bal will not change its velocity.

i think it's 35 meters