Shamshad Ali buys a scooter for Rs 22000. He pays Rs 4000 cash and agrees to pay the balance in annual instalment of Rs 1000 plus 10% interest on the unpaid amount. How much will the scooter cost him?

Answer

N/a

Explanation

Cost price = Rs. 22000
Cash payment = Rs. 4000
Remaining amount = Rs. 22000 - Rs. 4000 = Rs. 18000
amount of each instalment = Rs. 1000 + interest
`therefore" Number of instalments "= (Rs. 18000)/(Rs. 1000) = 18`
For first instalment
Principal = Rs. 18000
`therefore" Interest "= Rs. (18000 xx 10 xx 1)/(100) = Rs. 1800`
For second instalment
Principal = Rs. 18000 - Rs. 1000 = Rs. 17000
`therefore" "Interest = Rs. (17000 xx 10 xx 1)/(100) = Rs. 1700`
For third instalment
`"Principal "=Rs 17000-Rs 1000= Rs 16000`
`therefore "Interest "Rs(16000xx10xx1)/(100)= Rs 1600`
Progression formed by interests : 1800. 1700. 1600,…
It is an A.P.
Here a = 1800
d=1700-1800=1600-1700=-100
n=18
`therefore" "S=(n)/(2)[2a+(n-1)d]`
`=(18)/(2)[2xx1800+(18-1)(-100)]`
`=9xx1900=17100`
Now, total cost of scooter = Rs 22000 + Rs 17100
= Rs 39100