Answer : 4. "6630"
Explanation :

Answer: D) 6630 Explanation: Let first no. be "k" and multiple be "l"...start value of y with 3then,[(k x y) + {l x (l-1)}]Thus, we get 15 x 3 + 3 x 2 = 5151 x 4 + 4 x 3 = 216216 x 5 + 5 x 4 = 11001100 x 6 + 6 x 5 = 66306630 x 7 + 7 x 6 = 46452 Therefore, the missing number is 6630.