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Find the number of students who succeeded in exactly one subject.
A hotel provides the extra facilities: swimming, gym and fun-park facilities to its
guests. Among 300 guests arrived in the hotel, it was found that 60% guests used
swimming, 50% used gym and 40% used fun-park. Moreover, 30% used swimming
and gym facilities, 20% used gym and fun-park, 15% used fun-park and swimming
while 10% used all three facilities. By using the Venn-diagram, find the number of
guests who used
(i) none of the facilities (ii) only one facility (iii) only swimming and gym.

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