Brain Teasers
The Combination For $1,000,000
Recently, Brainiac, the extremely rich father of Brainiac Jr. had passed away. He had left one million dollars to Brainiac Jr.
However, the money was locked in a safe, and Brainiac Jr. would not get the money unless he knew the combination. Brainiac, being the brainiac that he is, left a number series for his son to work out. If he could not figure it out, he wouldn't get anything.
The combination is a 3-digit number, and to stop him randomly guessing he would only be able to try once every day.
Here is the series:
3, 11, 31, 55, 91, ...
Brainiac Jr. managed to finish the series, and get the million dollars. Can you?
However, the money was locked in a safe, and Brainiac Jr. would not get the money unless he knew the combination. Brainiac, being the brainiac that he is, left a number series for his son to work out. If he could not figure it out, he wouldn't get anything.
The combination is a 3-digit number, and to stop him randomly guessing he would only be able to try once every day.
Here is the series:
3, 11, 31, 55, 91, ...
Brainiac Jr. managed to finish the series, and get the million dollars. Can you?
Hint
It might make more sense if I change it to 2, 12, 30, 56, 90, ...Answer
The final number is 131.The series works from:
1 * 2 = 2 ( + 1 = 3 )
3 * 4 = 12 ( - 1 = 11 )
5 * 6 = 30 ( + 1 = 31 )
7 * 8 = 56 ( - 1 = 55 )
9 * 10 = 90 ( + 1 = 91 )
11 * 12 = 132 ( - 1 = 131 )
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