Solenoid constructed with 50 turns of wire and has inductance l. if we made another solenoid identical in length and cross sectional area but with 200 turns of wire it would have an inductance closest

It would have an inductance closest to 16 L.

Explanation:

Inductance for a one solenoid can be calculated with a formula following:

L=μ*N^2*A/l

Then, in this situation we are increasing the number of turns by 4 without any length change. First solenoid with 50 turn has inductance L which is:

L= μ*50^2*A/l=2500*μ*A/l

When we increase the number of turns by four, it will increase to:

L'=μ*200^2*A/l=40000*μ*A/l=16 L

total distance/total time

(85 + 82)/(5+3)

167/8

20 just over