Jim and Gina are swinging on adjacent, equal length swings at the school playground. Jim weights about twice as much as Gina Who, if either, will take less time to swing back and forth? What, if anything, will change if Jim swings while standing on the seat of his swing?

b

step-by-step explanation:

the word superfluous means unnecessary

if x = 1, then the answer is 3.5

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4