Select the set in which the numbers are related in the same way as are the numbers of the following sets.
(NOTE : Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 - Operations on 13 such as adding / subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)
(4,50,6),

(2,18,4)

( 4 , 50 ,6 ) , ( 2 , 18 , 4 )

[ { ( First number + Third number ) $$\div$$ 2 } $$\times$$ ( First number + Third number ) ] = Second Number

( 4 , 50 , 6 )

= $$[\frac{(4+6)}{2}]\times(4+6)]$$ 

= $$\frac{10}{2}\times10$$ = 50

50 = 50 ( Follow)

( 2 , 18 , 4 )

=$$[\frac{(2+4)}{2}]\times(2+4)$$

18 = 18 ( Follow)

​$$[\frac{(15+3)}{2}]\times(15+3)$$

​$$\frac{(12+5)}{2}\times (12+5)$$

8.5 $$\times$$ 17 

144.5 $$\neq$$​ 60 ( does not follow)

​$$\frac{(5+6)}{2}\times(5+6)$$

$$5.5\times11$$ 

60.5 $$\ne$$​ 62 ( does not follow )

​$$\frac{(2+3)}{2}\times(2+3)$$

2.5 $$\times$$ 5

12.5 $$\ne$$​  125  does not follow

Thus, the correct answer is (a) ( 15,  162 , 3 )

​​​