If the mean of the data
is 21, then k is one of the roots of the equation :
| Class | 5-10 | 10-15 | 15-20 | 20-25 | 25-30 | 30-35 |
|---|---|---|---|---|---|---|
| Frequency | 2 | k | 28 | 54 | k+1 | 5 |
is 21, then k is one of the roots of the equation :
- (A)
- (B)
- (C)✓ Correct
- (D)
Answer: (C)
Solution
With class midpoints , the total frequency is and . Setting the mean equal to , , so , giving and . Substituting into gives , so is a root of .
JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Single correct option