What will come in the place of question (?) mark in the following number series.
32, 40, 53, 76, ?, 172
Correct Answer :
114
Solution :
The correct option is 114.
To find the missing number in the given series, let us analyze the differences between consecutive terms:
Difference between 1st and 2nd term:
40 - 32 = 8
Difference between 2nd and 3rd term:
53 - 40 = 13
Difference between 3rd and 4th term:
76 - 53 = 23
Now, let us examine the sequence of differences obtained so far: 8, 13, 23, ...
Let us look at the differences of these differences (the second-order difference):
13 - 8 = 5
23 - 13 = 10
We can observe that the second-order difference increases by multiples of 5 (5, 10, 15, 20, ...):
Next second-order difference should be 15.
Therefore, the next difference to add to 76 will be:
23 + 15 = 38
Adding 38 to the 4th term (76) gives the missing number (?):
76 + 38 = 114
To verify, let us calculate the next step:
The next second-order difference would be 20.
The next term difference will be: 38 + 20 = 58.
Adding 58 to 114 gives: 114 + 58 = 172, which matches the final number in the series.
Hence, the missing number in place of the question mark (?) is 114.
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