Question
A certain sum is invested at a compound interest rate,
compounded annually, which grows to Rs. 12,240 after 2 years and to Rs. 17,625.6 after 4 years. If 80% of this sum is then invested at a simple interest rate of 7% per annum for 10 years, calculate the simple interest earned on this investment.Solution
Let the sum invested = Rs. 'K' Let the rate of interest = 'y'% p.a. Then, according to the question K X {1 + (y/100)}2 = 12,240 ....... (I) And K X {1 + (y/100)}4 = 17625.6 ........ (II) On dividing equation (I) from equation (II), we have; {1 + (y/100)}2 = 1.44 Or, 1 + (y/100) = 1.2 Or, (y/100) = 0.2 So, y = 20 Therefore, sum invested = 12240 ÷ {(100 + 20)/100}2 = 12240 ÷ 1.44 = Rs. 8,500 So, sum invested at simple interest = 8500 X 0.8 = Rs. 6,800 So, simple interest earned = 6800 X 7 X 10 ÷ 100 = Rs. 4760
If 15 men or 10 boys can finish a task in 18 days, how long will it take for a team of 12 men and 15 boys to complete the same task? (Calculate approxim...
A’ and ‘B’ together can complete a work in 22 days while ‘A’ takes 33 days to complete the same work alone. If ‘C’ is 20% more efficient t...
I and J together complete a piece of work in 20 days. If I alone can do it in 50 days, how many days will J alone take?
John does ½ piece of work in 3 hours, Joe does ¼ of the remaining work in 1 hour and George finishes remaining work in 5 hours. How long w...
Anil and Ashish receive Rs.1800 for work of 6 days. If Anil is 3 times efficient than Ashish, then find the daily wage received by Ashish.
A and B together can complete a work in 15 days, while B and C together can complete the same work in 20 days. If A, B, and C together can complete the ...
John, Emily, and Michael can each complete a task in 15 days, 20 days, and 18 days, respectively. They decide to work on the task alternately, starting ...
'C' can complete a work in 18 days whereas 'D' can do the same work in 30 days.They started working together but 'C' worked with 60% of his efficiency w...
- Aman and Bhuvan can complete a work in 21 days together, while Bhuvan alone can do it in 35 days. If the ratio of efficiencies of Aman and Chintu is 2:3, f...
A 210 litres mixture contains only water and phenyl in the ratio 3:2, respectively. If 60 litres of this mixture is replaced with 100 litres of alcohol,...
