Reduce, Reuse, Recycle, Re-think, Refuse and Repair :)
Peter R. N Childs has written: 'Mechanical design' -- subject(s): Machine design, Rotors, Engineering design, Design and construction
R. I. Seneviratne has written: 'To design a \\'
R. Matousek has written: 'Engineering design'
If r=9, then r*6 would be 9*6, or 54.
d = r + 6 now you make the equation relating what happened 6 yrs ago, remembering that then they were r-6 and d-6: dr = 2(r-6)(d-6) plug the first eqn into the second one and solve: r(r+6) = 2(r-6)(r) you can cancel an r, since r isn't 0! r+6 = 2(r-6) r=18 So Ricardo is 18 and his sis is 24.
R. M. Lawson has written: 'Design of stub girders' 'Fire resistant design of steel structures'
R. K. Penny has written: 'Design for creep' -- subject(s): Engineering design, Creep, Materials
R. Leacroft has written: 'Civic theatre design'
R. Mellor has written: 'Modern church design'
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R. Neal Shambaugh has written: 'Instructional design' -- subject(s): Instructional systems, Reflective teaching, Design
John R. Karsnitz has written: 'Engineering design' -- subject(s): Engineering design 'Society, Ethics and Technology'