voccubd wrote:

A seller bought some pens at a rate of 5 for Tk. 100. hey were separated into two stacks, one of which was sold at a rate of 3 for Tk. 100 and the other a rate of 6 for Tk. 100. What was the ratio of the number of pens in the two stacks if the seller made no overall profit or loss

a. 1:4

b. 1:5

c. 2:3

d. 1:2

e. None of the above

Use weighted average method..

So avg price is 100/5=20..

The two prices are 100/3 and 100/6..

So by Weighted Average method..

Number of 3 for 100/ number of 6 for 100= (20-100/6)/(100/3-20)=(20/6)/(40/3)= 20*3/40*6=1/4..

Ans A

Can you please elaborate on weighted average method or suggest any reference? Thanks in advance.