If goods be purchased for Rs.990 and one third sold at a loss of 10%. At what gain percent should the remainder be sold so as to gain 40% on the whole transaction ?

 65%

In this type of questions we do not need actual given amount so,

Let total = 90

After one third sold at a loss of 10% remaining  = 30 × \(\frac{9}{10}\) = 27

Total selling price should be 126 ( 140% of 90 )

Now two third has to be sold at = 126 - 27 = 99

Profit at which remaining has to be sold at = 99 - 60 = 39

= 39 × \(\frac{100}{60}\) = 65%