A man purchased some eggs at 3 for Rs. 16 and sold them at 5 for Rs. 36. Thus, he gained Rs. 168 in all. How many eggs did he purchase?
Let the number of eggs purchased be 'x'
CP of 3 eggs =Rs.16
CP of x eggs =163x
SP of 5 eggs =Rs.36
SP of x eggs =365x
Now,
Profit=SP−CP
168=36x5−16x3
168=108x−80x15
28x=168×15
28x=2520
x=90
Hence the man purchased 90 eggs.