Sebbl99 Posted November 28, 2007 Share Posted November 28, 2007 Hi Guys, need help with this one, no matter what I do I can`t come up with the solution to this prob Darla typed her term paper for two hours without a break. If her average words-per-minute speed increased by 20% in the second hour and her term paper was 7,920 words long, what was her typing speed during the second hour? Quote Link to comment Share on other sites More sharing options...
Ankost Posted November 28, 2007 Share Posted November 28, 2007 Let the rate in the 1st hour be x, then the rate in the 2nd hour will be 1.2x x+1.20x=7920 words/120 min. 2.20x=66 words/min x=30 words in the 1st hour 30*1.20=36 words in the 2nd hour Answer: 36 Quote Link to comment Share on other sites More sharing options...
krusta80 Posted November 28, 2007 Share Posted November 28, 2007 Let the rate in the 1st hour be x, then the rate in the 2nd hour will be 1.2x x+1.20x=7920 words/120 min. 2.20x=66 words/min x=30 words in the 1st hour 30*1.20=36 words in the 2nd hour Answer: 36 The answer is 72. You need to divide the right by 60 minutes per hour (NOT 120). Another way to do it is like this. Rate(hour1) = x words/min Rate(hour2) = 1.2*x words/min 7920 words = 60 minutes * x words/min + 60 minutes * 1.2 x words/min The minutes cancel out on the right hand side, and we can pull out the 60 from both terms... 7920 words = 60(x words + 1.2 x words) The words cancel from both sides... 7920 = 60 * (x+1.2*x) 2.2x = 132 x = 60 BUT, they want the second hour's rate, which is 60*1.2 = 72 words/min Quote Link to comment Share on other sites More sharing options...
yowas Posted November 28, 2007 Share Posted November 28, 2007 I agree with 72. Quote Link to comment Share on other sites More sharing options...
gmat asp Posted November 28, 2007 Share Posted November 28, 2007 me too, 72 it is. Quote Link to comment Share on other sites More sharing options...
Ankost Posted November 28, 2007 Share Posted November 28, 2007 The answer is 72. 7920 words = 60 minutes * x words/min + 60 minutes * 1.2 x words/min Thank you! This formula is better, more clear Quote Link to comment Share on other sites More sharing options...
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