7 + 77 + 777 + 777 +…………..+ n terms 7(1 + 11 + 111 + ………………………+ n terms) Multiply and divide by 9 9/9 × 7(1 + 11 + 111 +………………………+ n terms) 7/9 × (9 + 99 + 999 + …………………+ n terms) 7/9 × [(10 - 1) + (100 - 1) + (1000 - 1) +…………… + n terms] 7/9 × [(10 + 10² + 10³ +………+ n terms) – (1+1+1+………+ n terms)] 7/9 × [(10 + 10² + 10³ +………+ n terms) – n] In the series [10 + 10² + 10³ +………+ n terms] First term, a = 10 common ratio, r = 10 Sum of n terms = (a(rn-1))/((r-1)) ∴ Required answer = 7/9 [((10(10n-1))/9 - n)]
The Engineering division employs 25% of the company’s workforce, with Junior, Mid-Level, and Senior employees in the ratio 2:1:2. If 20% of the Junior...
Total number of men who went to cinema hall B is approximately how much percent less than the number of women who went to cinema hall A?
What is the difference between average number of article sold by B and D on all the four days?
What is the number of female workers in company P in 2019 and 2021 together?
If the ratio of number of wallets sold by store D on Monday and Friday is 7:13 respectively, then find the number of wallets sold by D on Friday.
On Monday, if difference between the time taken by the boat to go upstream and the time taken by the boat to go downstream is 15 hours, find the total t...
My grandmother was 9 times older to me 18 years ago. She would be 3 times of my age 9 years from now. 9 years ago, what was the ratio of my age to that ...
If in shop E, 20% of the laptops got damaged and remained unsold, then find the number of laptops sold by the same shop.
Find the ratio of number of mobile phones sold by shopkeeper C to that by shopkeeper E.
What is the difference between the number of Umbrella sold in city B and the number of Raincoat sold in city A?
