Of the families in City X in 1991, 60 percent owned a personal computer. The number of families in City X owning a computer in 1993 was 20 percent greater than it was in 1991, and the total number of families in City X was 9 percent greater in 1993 than it was in 1991. what percent of the families in City X owned a personal computer in 1993?  Choices
A) 59 %  B) 55 %  C) 63 %  D) 66 %  E) 68 %

Rationale: "say a 100 families existed in 1991 then the number of families owning a computer in 1991 - 60 number of families owning computer in 1993 = 60 * 120 / 100 = 72 number of families in 1993 = 109 the percentage = 72 / 109 * 100 = 66 % . answer : d"
Answer: D