In the following question, select the number/symbol that will replace the question mark (?) to complete the analogy:
90 : ? :: 72 : 240
Show answer & explanation
Correct answer: D
Explanation
72 : 240
72 = 8 × 9 = n(n + 1)
⇒ n = 8
Now,
240 = (n + 7)(n + 8)
= (8 + 7)(8 + 8)
= 15 × 16
= 240
Apply the same rule to 90:
90 = 9 × 10 = n(n + 1)
⇒ n = 9
Hence,
? = (n + 7)(n + 8)
= (9 + 7)(9 + 8)
= 16 × 17
= 272
Correct answer: 272