Extra help on SAT math Problem!?

Question

1) The ratio of smokers to nonsmokers on a particular flight was 2:3. Smoking passengers represented five more than 1/3 of all the passengers aboard. How many passengers were on that flight?
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Let's say
s:smoker ns: non smoker
s=2x ns=3x
and
s=1/3(s+ns)+5
s=1/3(5x)+5
s=5x/3+5
s=(5x+15)/3
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I got this far... but... i just do not what to do next..
Help me with next step!!!
Please~~~
Thank you ~

Answer 1

Let the smokers and non-smokers be 2x and 3x respectively.
total passengers=5x
By the problem.
2x=(5x/3)+5
or,6x=5x+15 [multiplying both sides by 3]
or,6x-5x=15
or,x=15
No of passengers on the flight
=5x
=5*15=75

Answer 2

Let
s = number of smokers
n = number of nonsmokers

s/n = 2/3
s = (1/3)(n + s) + 5

From the first equation.
s/n = 2/3
(3/2)s = n

Substitute into the second equation.

s = (1/3)(n + s) + 5
s = (1/3)[(3/2)s + s] + 5 = (1/3)[(5/2)s) + 5 = (5/6)s + 5
s/6 = 5
s = 30

n = (3/2)s = (3/2)(30) = 45

n + s = 45 + 30 = 75

There were 75 people on the flight.

Answer 3

you can cancel out x in the second step, or simply don't use it at all:
s = 2x, ns = 3x...
s = 2*ns/3 <<=eqn1
s = (1/3 * (s + ns)) + 5 <<=eqn2
2 equations, 2 unknowns
total passengers = s + ns
***DONT FORGET THE LAST PART
you can bet that there will be 2 incorrect choices, one with the value for s, the other for the value for ns, but the question asks for -total passengers-. that's the trickiest part about the SATs