If the seventh number is 21 and the ninth number is 55; Provided the group of numbers constitute n arithmetic progression; the tenth number is; 72
According to the question:
- We are required to determine the tenth number.
If assumed that the group of numbers constitute an arithmetic progression;
Hence, there are 2. terms between the seventh and ninth term;
Therefore, 2d = 55-21
On this note, the tenth term is just one term away from the ninth term;
Ultimately, the tenth term is; 55 + 17 = 72
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