Before the regime change, the National Museum regularly displayed only one third of the artifacts in its collection; the other two thirds were kept in storage. The National Museum’s curator estimates that one seventh to one fifth of the artifacts in the museum’s collection disappeared during the regime change. If the National Museum now wishes to display the same number of artifacts as it did before the regime change, and if none of the missing artifacts are recovered, then the museum will keep in storage:	Choose the correct choice from the following options
A) 4/5 to 6/7 of artifacts in collection
B) 9/14 to 13/20
C) 3/5 to 5/7
D) 7/12 to 11/18
E) 7/18 to 5/12
let T be total number of artifacts initially.   stolen (1/7)T to (1/5)T   left (6/7)T to (4/5)T = new total   1/3 for display T/3   storage (6/7)T -T/3 to (4/5)- T/3   11/21 T to 7T/15   so storage to new total = (11T/21) / (6T/7) to (7T/15) / (4T/5)   i.e 11/18 to 7/12   Answer is 7/12 to 11/18.
<result>D</result>
Before the regime change, the National Museum regularly displayed only one third of the artifacts in its collection; the other two thirds were kept in storage. The National Museum’s curator estimates that one seventh to one fifth of the artifacts in the museum’s collection disappeared during the regime change. If the National Museum now wishes to display the same number of artifacts as it did before the regime change, and if none of the missing artifacts are recovered, then the museum will keep in storage: