A sum of Rs 1550 was lent partly at 5% and partly at 8% p.a. simple interest. The total interest received after 3 years was Rs 300. The ratio of the money’s lent at 5% to that lent at 8% is:
(a) 5 : 8
(b) 8 : 5
(c) 16 : 15
(d) 31 : 6