Directions (Set of 3 questions): In the following question, select the number which can be placed at the sign of question mark (?) from the given alternatives.
Solution
2 + 3 + 7 + 8 = 20
7 + 3 + 6 + 4 = 20
3 + 5 + 7 + ? = 20
$\Rightarrow ? = 20 - 15 = 5$