Find the rate of simple interest per annum at which a sum of ₹1,200 will amount ₹1,800 in 4 years.

12.5% 14% 15% 10%

12.5%

Simple interest of 4 years = 1800 - 1200 = 600 Simple interest of 1 years = 150 Simple Interest = \(\frac{Principal ×Rate × Time }{100}\) 150 = \(\frac{1200 ×Rate × 1 }{100}\) Rate = \(\frac{150 × 100 }{1200×  1  }\) = 12.5%