Find the sum of the numbers between 200 and 500.Which is the multiple of 7
Answers
Answer:
- 500 + 200 = 700
- 700 multiple of 7 = 1400
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QUESTION :
Find the sum of the numbers between 200 and 500 which is the multiple of 7.
SOLUTION :
Given that,
Numbers in between 200 & 500 which is a multiple of 7 are : 203,210,217.....497
Therefore,the AP series is
→ 203,210,217....497
- a1 = 203 & a2 = 210
Common difference (d) = a2 - a1
= 210 - 203
= 7
Therefore,the common difference (d) is 7.
Now we have
- a = 203, d = 7, an = 497, n = ?
➢ To find number of terms...
⟹ an = a + (n - 1)d
- substitute the values to get no.of terms
➡ 497 = 203 + (n - 1)7
➡ 497 = 203 + 7n - 7
➡ 497 = 196 + 7n
➡ 7n = 497 - 196
➡ 7n = 301
➡ n = 301/7
➡ n = 43
Therefore,the no.of terms are 43
➢To find the sum of the terms, we need to use the formula
⟹ Sn = n/2 [ 2a + (n - 1)d ]
- Substitute the values to get sum of terms.
➡ S43 = 43/2 [ 2(203) + (43 - 1)7 ]
➡ S43 = 43/2 [ 406 + (42)7 ]
➡ S43 = 43/2 [ 406 + 294 ]
➡ S43 = 43/2 [ 700 ]
➡ S43 = (43 × 700)/2
➡ S43 = 43 × 350
➡ S43 = 15050
Therefore,the sum of the numbers between 200 and 500 which is the multiple of 7 is 15050.