Maths Question?

By mass, a certain road bed material is 75%(per cent) crushed rock and another material is 30% crushed rock.

How many tonnes of each must be mixed in order to have 250 tonnes of material that is 50% crushed rock.
(1 tonne = 1000 kg)

Any ideas would be appreciated thanks. :wink:

Tags:

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

x......part of certain road bed material x+y=250
y.....part of another material

75x+30y = 250 * 50 /:10
7.5x+3y=1250
7.5x+3(250-x)=1250
7.5x+750-3x=1250
4.5x=500
x=111.1111 t

y=250-x
y=138.8888 t

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-20010 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.