Find out the wrong number in the following series.
98, 79, 62, 47, 33, 23, 14
Show answer & explanation
Correct answer: C
Explanation
Check the differences
98-79=19
79-62=17
62-47=15
47-33=14(wrong)
33-23=10
23-14=9
The differences are: 19, 17, 15, 14, 10, 9.
It seems the differences should decrease by 2 each time:
19, 17, 15, 13, 11, 9
Let’s apply it:
98-19=79
79-17=67
62-15=47
47-13=34(but given 33)
34-11=23
23-9=14
So, 33 is wrong number.
Hence, option (3) is the correct answer.