In the year 2000, Rodrigo invests some money in a savings account with 4% annual
interest, compounded monthly.
In 2010, Ten years later, Rodrigo opens a new account with 5% annual interest compounded
monthly, and he invests $200 a month every month for the next three years.
At the end of 2013. Rodrigo is told the total amount of money in his two accounts is $33 000
How much money did Rodrigo originally invest in the year 2000?
Answers
Answer:
. Robin lends Rs.9 to Rahul on the condition that the loan is repayable in 10 months in 10 equal installments of Re.1 each. Find the rate of interest per annum.
Sol. Let the rate of interest per month be r
Total amount repaid = Rs.10
Interest = Re.1
r/100(9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1) = 1
So r = 100/45
Hence, the rate of interest per annum = (100/45) 12 = 26 2/3%
Ex. 2. A milkman borrowed Rs. 2500 from two money lenders. For one loan, he paid 5% p.a. and for the other he paid 7% p.a. The total interest paid for two years was Rs. 265. How much did he borrow at 5% and how much at 7%?
Sol. Let the loan be Rs. x at 5% p.a and Rs (2500 – x) at 7% p.a.
Total interest for 2 years = ([X×5×2+(2500-X)×7×2])/100
Given simple interest for the total amount = Rs. 265
([X×5×2+(2500-X)×7×2])/100 = 265
Solving, we get x = 2125
Amount borrowed at 5% = Rs. 2125
Amount borrowed at 7% = Rs. 375