Question

a certain sum at a certain rate percent per annum simple interest becomes rupees 9,300 in 2 years and rupees 12,000 in 5 years. find the principal and rate of interest​

Answer 1

Step-by-step explanation:

Principal + Interest for 5 yrs = Rs. 2250

(-) Principal + Interest for 2 yrs = (-) Rs. 2100

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Interest for 3 yrs = Rs. 150

Interest for 2 yrs = Rs. 150÷3×2

= Rs. 100

Now,

Interest for 2 yrs = Rs. 100

Amount for 2 yrs = Rs. 2100

Therefore, Principal = Rs. (2100-100) = Rs. 2000

Time = 2 yrs

Therefore, Rate of interest = Interest × 100 ÷ Principal × Time = 100×100÷2000×2 = 2.5%

Therefore, Principal = Rs. 2000

and Rate of interest = 2.5 % per annum