Question:

Find the missing term in the series: \[ 121,\;112,\;104,\;97,\;91,\;\_\_\_,\;82,\;79,\;77 \]

Show Hint

When differences form consecutive numbers in reverse order, continue the sequence carefully.
Updated On: Jul 15, 2026
  • \(86\)
  • \(85\)
  • \(84\)
  • \(83\)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

Concept: Observe the pattern of subtraction. The numbers decrease by consecutive integers.

Step 1:
Find the differences.
\[ 121-112=9 \] \[ 112-104=8 \] \[ 104-97=7 \] \[ 97-91=6 \] Pattern: \[ -9,\;-8,\;-7,\;-6 \] So next should be: \[ -5,\;-4,\;-3,\;-2 \]

Step 2:
Find the missing term.
After: \[ 91 \] subtract \(5\): \[ 91-5=86 \] Check further: \[ 86-4=82 \] \[ 82-3=79 \] \[ 79-2=77 \] Pattern matches perfectly. Thus, the missing term is: \[ \boxed{86} \]
Was this answer helpful?
0
0