Question

Find the sum of first 25natural numbers divided by 7

Answer 1

Answer:

2275

Concept used:

1 + 2 + 3 + ...... + n = [n(n + 1)] / 2

Step-by-step explanation:

⇒ Least (1st) natural number as multiple of 7 = 7

⇒ Last (25th) natural number as multiple of 7 = 25 × 7 = 175

⇒ Sum of the numbers,

• 7 + 14 + 21 + 28 + ...... + 175
• 7 [1 + 2 + 3 + 4 + ...... + 25]
• 7 [(25 × 26) / 2]
• 7 [650 / 2]
• 7 × 325
• 2275

⇒ The answer is 2275.