Question

What is the next number of the following sequence ?

21, 77, 165, 285, ......
A) 404
B) 415
C) 426
D) 437

Answer 1

Look carefully ,
3×7=21
7×11=77
11×15=165
15×19=285
19×23=437
There is increase of 4 in multiplication rows.
Therefore, answer=437

Answer 2

Answer:

27, 77, 165 ,285, 437

Answer is D, 437

Step-by-step explanation:

Given 21, 77, 165, 285

Let us check the series

Here

21+(8*7) = 21+56 = 77

77+(8*11) = 77+88 = 165

165+(8*15) = 165+ 120 = 285

Here, 7, 11, 15 are having a common difference of 4, so the next number to be multiplied with 8 is 15+4 = 19

So, the next number is

285 +(8*19) = 285 + 152 = 437

So, the answer is 437(D)