Convert the 6 seconds to hours:
5 seconds x x 1/60 ( minutes per seconds) x 1/60 (Hours per minute) = 6/3600 = 1/600 hours.
Distance = speed x time
Distance = 585 x 1/600 = 585/600 = 0.975 miles
Convert miles to feet:
0.975 x 5280 = 5,148 feet
The plane traveled 5,148 feet in 6 seconds.
For this, all you have to do is create equations where all you have to do is change the x value. The equation for gym A would be 35 + 42x, where x is the number of months he has the membership, and the first number is the initial fee. The equation for gym B would be 65 + 36x, following the same rules. Now all you have to do is set both of these equations equal to each other:
65+36x=35+42x
Solving this equation results in x=5, which means that he has to have the memberships for 5 months for them to be equal. Now just plug that in to one side of the equation to get the amount he has to spend:
65+36(5) = $245