Saved Bookmarks
| 1. |
Show that the sum of all odd integers between1to 1000 divisible by 3is 83667 |
| Answer» A.P : 3,9,15,------------999. Here a= 3, d=6, An = 999. An= a+ (n-1)d999=3 + ( n-1)6 999=3+ 6n - 6999 = 6n- 3999+3=6n1002=6n1002/6=n167=n.Sn = n/2 [2a+(n-1) d ]S167 = 167/2 [2×3+(167-1)×6] = 167/2 [6+166×6] = 167/2 [1002] = 167/2× 1002 =167×501 = 83667. Hence proved | |