Question

At simple interest a sum becomes (6/5) of itself in 2½ years. The rate of interest per annum is

(a) 6% (b) 7½% (c) 8% (d) 9%

Answer 1

(c) 8%

Because,

Let the required sum be ₹ x

Rate of interest = r %

Time = 2½ years = 5/2 years

Amount = (6/5) × sum

Amount = principal + SI

(6/5) × x = x + [(P × R × T)/100]

= (6/5) x = x + [(x × r × 5)/ (100 × 2)]

= (6/5) = (1 + (r/40))

= r = (40 × (1/5))

= r = 8%