Question 1010453
Hi there,
The total cost after 7 months' membership will be $335
Make initiation fee = x
Make monthly due = y
x + 7y = $335
and after 1 1/2 year, $830. 
x + 18y = $830
..............
x + 7y = $335.......(1)
x + 18y = $830......(2)
Subtract (1) from(2)
....11y = $495
....y   = $45
Substitute y = $45 in (1)
x + 7y = $335
x + 7($45) = $335
x + $315 = $335
x = $335 - $315
x = $20
Initiation fee = $20
Monthly due = $45
Hope this helps :-)