SOLUTION: There are 648 more blue pens than red pens in stationary shop. After 1/6 of the blue pens and 3/4 of the red pens were sold, there were 1338 more blue pens than red pens left. How

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Question 1004535: There are 648 more blue pens than red pens in stationary shop. After 1/6 of the blue pens and 3/4 of the red pens were sold, there were 1338 more blue pens than red pens left. How many pens were there at first.
Answer by maxitee(11) About Me  (Show Source):
You can put this solution on YOUR website!
Let's call the Blue pens B and the Red pens R.

B+=+R+%2B+648 (From the question)... Equation(i)
Upon selling 1/6 of blue pens, we now have a new amount of Blue pens. We shall call this new amount of blue pen Bn)
Bn+=+B-B%2F6, (Where B is the original amount of Blues)
Rn=++R+-+3R%2F4 (Same thing applies to Reds after selling 3/4)
Bn+=+Rn+%2B+1338 (Because blues had 1338 more than red after sales)
B+-+B%2F6+=+R-+3R%2F4+%2B+1338 (Substituting the values of Bn and Rn into above equation)
5B%2F6+=+R%2F4+%2B+1338
%285R+%2B+3240%29%2F6+=+%28R%2B5352%29%2F4
6R+%2B+32112+=+20R+%2B+12960
-14R+=+12960+-+32112
14R+=+19152
R= 1368 (Total amount of RED before sales)
B = 2016 (Total amount of Blues before sales)
How many pens? Simply add up B and R. I will allow you do that..
Enjoy!