The solution to the above question is B: 12.5%
This question seems hard at the first glance, but making a Venn Diagram makes it easy to understand.
Speeding Ticket.PNG [ 8.25 KiB | Viewed 398 times ]
M represents the set of all motorists
S represents the set of motorists who exceeded speed
T represents the set of motorists who exceeded speed and got a ticket
The question says that 20% of all motorists who exceeded speed did not get a ticket.
Have a look at the Venn Diagram. Which area represents such motorists?
The orange one.
So, if orange area is 20% of the set S, then what % of S will be the red area?
It's also given that 10% of all motorists exceed speed and get a ticket. Which area of the diagram represents these motorists?
Again, the red area.
So, we get the equation:
10% of M = 80% of S
So, S = 1/8 of M = 12.5% of M.
Hence, Option B.
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