If the profit was Rs. 600 in 1993, then what was the profit in 1990?

Correct Answer : D.

we can solve it by ratio, if the profit of 1993 was 600 and cost = 110. Let the profit be x for 1990 and the cost was 100, $then \frac{600 }{110} = \frac{x}{100}$
[assuming the ratio of profit and cost be same]
then x = 545.