JEE Main & Advanced
Mathematics
Functions
Question Bank
Self Evaluation Test - Relation and Functions-II
question_answer
Let \[f:\{2,3,4,5\}\to \{3,4,5,9\}\] and \[g:\{3,4,5,9\}\]\[\to \{7,11,15\}\] be functions defined as \[f(2)=3f(3)=4,f(4)=f(5)=5,g(3)=g(4)=7,\] and \[g(5)=g(9)=11.\] Then gof (5) is equal to
A)5
B)7
C)11
D)1
Correct Answer:
C
Solution :
[c] We have \[gof(2)=g(f(2))=g(3)=7,gof(3)\] \[=g(f(3))=g(4)=7,gof(4)=g(f(4))=g(5)=11\]and \[gof(5)=g(5)=11.\]