Question

What term should replace the question mark ?
78, 79, 81, ?, 92, 103, 119

• A. 88
• B. 85
• C. 84
• D. 83

Answer 1

The correct option is B 85

The differences of terms are 1, 2, 4, 7, 11, 16, 22....

So the difference is increasing by adding 1, 2, 3, 4, 5, 6, 7....

2nd term$=78+1=79$

3rd term$=79+1+1=79+2=81$

4th term$=81+2+2=81+4=85$

5th term$=85+4+3=85+7=92$

6th term$=92+7+4=92+11=103$

7th term$=103+11+5=103+16=119$

Hence $85$ replaces question mark.