Concept:For independent events, complements are also independent, so P(E′/F)=P(E′) and P(F′/E)=P(F′).Explanation:Given P(E)=53​ and P(F)=103​.Since E and F are independent, E′ and F are independent.So, P(E′/F)=P(E′)=1−P(E)=1−53​=52​.Similarly, P(F′/E)=P(F′)=1−P(F)=1−103​=107​.Now add them: P(E′/F)+P(F′/E)=52​+107​.Convert: 52​=104​.Thus, 104​+107​=1011​.Answer:1011​