-

1 + 1 + 1 + 1 + 1 + 1 
is equal to : 3.5 5.7 7.9 9.11 11.13 13.15
-
-
2 45 -
4 45 -
7 45 -
2 15
-
Correct Option: D
| = | ![]() | + | + | + | + | + | ![]() | ||||||
| 3.5 | 5.7 | 7.9 | 9.11 | 11.13 | 13.15 |
| = | ![]() | + | + | + | + | + | ![]() | |||||||
| 2 | 3.5 | 5.7 | 7.9 | 9.11 | 11.13 | 13.15 |
| = | ![]() | + | + | + | + | + | + | + | + | + | + | + | ![]() | |||||||||||||
| 2 | 3 | 5 | 5 | 7 | 7 | 9 | 9 | 11 | 11 | 13 | 13 | 15 |
| = | ![]() | − | ![]() | = | ![]() | ![]() | |||||
| 2 | 3 | 15 | 2 | 15 |
| = | × | = | |||
| 2 | 15 | 15 |
Second Method :
| = | + | + | + | + | + | ||||||
| 3.5 | 5.7 | 7.9 | 9.11 | 11.13 | 13.15 |
Here, n = 3 and r = 6
| = | ![]() | − | ![]() | |||
| 2 | n | n + 2r |
| = | ![]() | − | ![]() | |||
| 2 | 3 | 3 + 2 × 6 |
| = | ![]() | − | ![]() | |||
| 2 | 3 | 15 |
| = | ![]() | ![]() | = | |||
| 2 | 15 | 15 |