The white watch is costlier than exactly three watches. The red watch is costlier than the white watch but cheaper than the blue watch.
Case 1:
_____ > Blue > Red > White > _____ > _____ > _____
Case 2:
Blue > _____ > Red > White > _____ > _____ > _____
Case 3:
Blue > Red > _____ >White > _____ > _____ > _____
The pink watch is cheaper than the yellow watch but not the cheapest. The brown watch is costlier than yellow watch but cheaper than red watch. The purple watch is cheaper than the white watch.
So, case 1 and case 2 are invalid.
Case 3:
Blue > Red > Brown > White > Yellow > Pink > Purple
The price of the purple coloured watch is the lowest.