Correct Answer - Option 1 : 7
The logic follows here is :
First number = (Second number)2 - 1
Or,
Second number = √ (First number + 1)
For 24 : 5,
5 = √ (24 + 1)
5 = √ 25
5 = 5.
For 48:?
? = √ (48 + 1)
? = √ 49
? = 7.
Hence, the correct answer is "7".