Question

16 16 40 140 840 7980?

Answer 1

Solution:

16 x 1 = 16

16 x 2.5 = 40

40 x (2.5 + 1.0) = 140

140 x (3.5 + 2.5) = 840

840×(6+3.5)= 7980

7980 x (9.5 + 6) = 123690.

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1+2.5=3.5
2.5+3.5=6
3.5+6=9.5
6+9.5=15.5


Hence the missing number is 123690
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Hope this will help you....