Question #ac2d1

Question

↳Redirected from "What is an example of an Ideal gas law practice problem?"

1615 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-06-16T12:47:19

I got #15# pens at #$6# each.

Call the number of pens #x# and the cost of one pen #y# we get:

At the original price:
#xy=90#

If we subtract #$1# from the original price we can buy #3# more pens or:
#(x+3)(y-1)=90#

so
#(x+3)(90/x-1)=90#
#90-x+270/x-3=90#
#-x^2+270-3x=0#

Using the quadratic Formula we get that:

#x_1=15# (we get a negative solution as well #x_2=-18#).

So the total number of pens is #15# and the cost of one pen will be:
#y=90/x=90/15=$6#