A sum of Rs. 1500 is invested at simple interest for x months. If the rate of interest is \(\frac{x }{9}\)% per annum, then the sum grows to Rs. 1580. What is the value of x ?
Answer & explanation
Correct answer: option 4
x months = \(\frac{x }{12 }\) years
Simple interest of x years = 1580 - 1500 = 80
By using formula ,
Simple Interest = \(\frac{Principal ×Rate × Time }{100}\)
80 = \(\frac{1500 × x × x }{100 × 9 × 12 }\)
16 = \(\frac{ x × x }{ 9 × 4 }\)
x × x = 576
x = 24