These triangles are not similar. The triangles are not similar because the proportion 8/9 = 2/3 is false.
Notice that
This means you are looking for
Chebyshev's theorem states that for any constant
,
which means
In other words, at least 75% of the geysers will have eruptions lasting between 1.67 and 5.95 minutes. Out of 32 geysers, then, one can expect at least 24 of them to have eruptions with between these durations.
Well, 4 people are each paying the same amount... the price they are all paying together is $12... basically, do 12 / 4, and you get three.