what is the sum of the sequence 10 20 30 ....1000?
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Step-by-step explanation:
sum from 10 to 1000 is 50500
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Hello !!
Find the number of terms.
An = A1 + (n - 1) × d
1000 = 10 + (n - 1) × (20 - 10)
1000 = 10 + (n - 1) × 10
1000 = 10 + 10n - 10
1000 = 10n - 10 + 10
1000 = 10n
n = 1000/10
n = 100
Now , you find the sum of the first 100 terms.
Sn = (n/2) × [2A1 + (n - 1) × d]
S100 = (100/2) × [2(10) + (100 - 1) × 10]
S100 = 50 × [20 + 99 × 10]
S100 = 50 × [20 + 990]
S100 = 50 × 1010
S100 = 50500
Final result : 50500.
I hope I have collaborated !
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