Question 1131844
bikes + scooters + duneb = 165
d = 1/3b
s = 3b-4
let's substitute in the first formula above:
b + s + d = 165
b + 1/3b + 3b - 4 = 165
4 1/3b = 169
b = 169/4 1/3 =  39 
There are 39 bikes
And the dune buggies are 1/3 of that, so there are 39(1/3) = 13 dune buggies
And scooters are 4 less than 3 x the number of bikes: (39 x 3) - 4 = 113 scooters
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Check:
Add the totals I gave you:
39 + 13 + 113 = 165 This is the correct answer