A man borrows `₹8000` and agrees to repay with a total interest of `₹1360` in 12 monthly installments, each installment being less than the preceding one by `₹40`. Find the amount of the first and last installment.

Mr. Shah borrows ₹4000 and agrees to repay with a total interest of ₹500 in 10 installments, each installment being less than the preceding installment by ₹10. What is the first and the last installment?

A farmer borrows ₹1000 and agrees to repay with a total interest of ₹140 in 12 installments, each installment being less than the preceding installment by ₹10 . What should be the first installment?

One person borrows Rs 4000 and agrees to repay with a total interest of Rs 500 in 10 instalments. Each instalment is less than the preceding instalment by Rs 10 . What would be the first and last instalments?

Mr. Ajay borrows ₹3,25,000. He paid ₹30,500 in the first month and then each installment being less than the preceding installment by ₹1500 he pays the rest. How long will it take to clear his loan?

An amount of Rs.5000 is invested in three types of investments, at interest rates 6% , 7%, 8% per annum respectively. The total annual income from these investment is 350/- If the total annual income from first two investment is Rs. 70 more than the income from the third,find the amount of each investment using matrix method.