MadeEasy Subject Test: Databases - Joins

Question

I think the answer should be 300 because in relation Q, C and E collectively distinguish a tuple from another tuple.So there can be duplicate values in C and then the natural join of P and Q will give 300 tuples.Same case can be considered when we natural join P,Q with R. Am I correct?? 

Answer 1

No its 100 you are forgetting the difference between intersection and natural join. Try this
https://gateoverflow.in/2344/gate2010-43