A trader purchased a wall clock and a watch for a sum of Rs. 5070. He sold them making a profit of 10% on the wall clock and 15% on the watch. He earns a profit of Rs. 669.50. Find the cost price of the wall clock and that of the watch.
Let the price of the watch is x
Then, The price of the clock is 5070−x
So,
(x×15%)+((5070−x)×10%)=669.5
0.15x+507−0.1x=669.5
0.05x=669.5−507=162.5
x=162.50.05
x=3250
Thus the price of the watch is Rs3250
And the price of the clock is 5070−3250=1820