Date: 02/01/97 at 11:07:47 From: frank kreager Subject: Software Sales Hi, I am doing word problems and am having a lot of trouble putting them into mathematical equations. Once I get the mathematical equation, I don't have any difficulties. For instance: The three best selling software applications at one computer store are priced as follows: spreadsheet $150, database $195, word processing, $210. Spreadsheet and database programs are sold in equal numbers, but 15 more word processing applications are sold than the other two combined. The three applications together generated sales of $72,000. How many spreadsheets are sold? I would appreciate any assistance you can give me on how to transfer word problems into mathematical equations. Thanks
Date: 02/03/97 at 21:45:58 From: Doctor Wallace Subject: Re: Software Sales Hi Frank! Translating English to math gets easier the more you do it - you eventually get used to the phrases used. I can offer some general help: When you see It usually means ------------- -------------------- more than, sum, total, combined + less than, difference of - of, product x is, the same as, equal to = Let's go through your problem step by step and maybe it will shed some light on the process. The first thing to do is write down what you know: - Cost of spreadsheet program: $150 - Cost of database program: $195 - Cost of word processing program: $210 - Number of spreadsheet programs sold = number of database programs sold - 15 more word processing programs are sold than the number of spreadsheet and database programs sold Since the number of spreadsheet programs sold is equal to the number of database programs sold, we will let X equal the number of EACH that is sold. We know that 15 more word processing programs are sold than the other two combined. To translate this into English, we first need to ask what is the "other two combined". It's simply the total number of spreadsheet and database programs sold. This is equal to X + X, which is the same as 2X. If 15 more word processing programs than this are sold, then the number of word processing programs sold must be 2X + 15. If we multiply the number of each program sold times the cost of each program, that gives the amount of money made from each program. So, if we add those values together for each of our three programs, we should get the total sales, which we are told are $72,000. Sales from spreadsheet programs: 150X Sales from database programs: 195X Sales from word processing programs: 210(2X + 15) If we add these three things up and set them equal to $72,000, then we can solve for X, which is the total number of spreadsheet programs sold. This is the answer that we are supposed to find. It also happens to be the total number of database programs sold. Our equation is: 72,000 = 150X + 195X + 210(2X + 15) 72,000 = 150X + 195X + 420X + 3150 Distribute the 210 72,000 = 765X + 3159 Add like terms with X's in them 68,850 = 765X Subtract 3150 from each side 90 = X Divide each side by 765 This means that 90 spreadsheet programs are sold. I hope this helps, Frank. If you need more assistance, don't hesitate to write back! -Doctors Rachel and Wallace, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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