Question

12, 27, 85, 345, ?

• A. 1737
• B. 1380
• C. 1725
• D. 1731

Hint:

Look for parallel progressions in the multiplier and the addend.

Answer 1

The Correct Option is D

Multiply by \(2,3,4,\ldots\) and then add \(3,4,5,\ldots\): \[ 12\!\times\!2{+}3=27,\quad 27\!\times\!3{+}4=85,\quad 85\!\times\!4{+}5=345. \] Next: \[ 345\!\times\!5{+}6=1725{+}6=1731. \] \[ \boxed{1731} \]