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Shamshad Ali buys a scooter for Rs. 2200. He pays Rs. 4000 cash andagrees to pay the balance in annual instalments of Rs. 1000 plus 10% intereston the unpaid amount. How much the scooter will cost him? |
Answer» `rs 2200 -> ` cost `1yr -> 1000 + 10/100 xx 18000 = 1000 + 1800` `2 yr-> 1000 + 10/100 xx 17000 = 1000 + 1700` `n yr -> 1000 + 10/100 (18000 - (n-1)1000)` `= 1000+ 1800 + 100 - n100` `= 2700 - n(100)` `S_n = [ sum 2900 - n(100)] + 4000` `= 2900n - 100(n(n+1))/2 + 4000` `= 52200 - 500 xx 9 xx 19 + 4000` `= 56200 - 17100` `= 39200 rs` Answer |
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