Rahul went into deep sleep after the previous dream; he saw one more dream in which, there was an equation in a box (Figure)
The "a” in yellow colored box can take value 10 and the "a” in the green box can take value 4 because 10 + 4 = 14.
In an equation, a symbol cannot have two different values. So "a” can only be equal to 7, because 7 + 7 = 14.