Hey,
If we look at the question we get to know that,
7+9=2*(16)=32
3+6=2*(9)=18
that is twice the sum of the numbers gives the answer.
therefore the answer for 5+4 will be
5+4=2*(9)=18
Therefore,
18 is the required answer for 5+4.
7+9=32
3+6=18
5+4= 18
I hope this helps.
All the best!
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile