livendive 8 #26 May 9, 2006 Quote1. If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? Sally paints 1/4 houses per hour, John paints 1/6 houses per hour. Lowest common denominator is 12, so together they paint 5/12 houses per hour. 12/5=2.4 hours, or 2 hours and 24 minutes 2. Alfred wants to invest $4,000 at 6% simple interest rate for 5 years. How much interest will he receive? .06 * 4000 = 240/year * 5 years equals $1200 3. If the average of three numbers is V. If one of the numbers is Z and another is Y, what is the remaining number? (answer is a formula consisting of those three letters) (X + Y + Z)/3 = V X + Y + Z = 3V X + Z = 3V - Y X = 3V - Y - Z 4. Jim can fill a pool carrying bucks of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1 ½ hours. How quickly can all three fill the pool together? See first answer. Jim = 6/3 pools per hour Sue = 4/3 pools per hour Tony = 2/3 pools per hour Collectively = 12/3 pools per hour, or 4 pools per hour, so 1 pool will take them 15 minutes. 5. What simple interest rate will Susan need to secure to make $2,500 in interest on a $10,000 principal over 5 years? 5X * 10000 = 2500 5X = .25 X = .05, or 5 percent Blues, Dave"I AM A PROFESSIONAL EXTREME ATHLETE!" (drink Mountain Dew) Quote Share this post Link to post Share on other sites
livendive 8 #27 May 9, 2006 QuoteOk... since I was right I will have to try to put the logic here. 1) Add the too rates to get a combined rate: 1house/4hours + 1 house/6hours = 3/12+2/12 = 5houses/12hours Therefore:1 house would be done in 12/5 hours which is 2 hours 24 minutes. 2) 4000*0.06*5 = 1200 3) (x+Z+Y)/3 = V x+Z+Y = 3V x = 3V-Z-Y 4) Same as 1: add the rates: 1/30minutes + 1/45minutes + 1/90 minutes = 3/90+2/90+1/90 = 5/90minutes Therefore one would be done in 90/5minutes or 15 minutes 5) 10,000*x*5 = 2500 x=0.05 or 5% Alright, so you got 'em out there before I did, but at least I hadn't checked the correctness of my answers before posting the work that led to 'em. Blues, Dave"I AM A PROFESSIONAL EXTREME ATHLETE!" (drink Mountain Dew) Quote Share this post Link to post Share on other sites
mcneill79 0 #28 May 9, 2006 Posting logic takes energy... didn't feel like posting if it was wrong. I posted my answers first Quote Share this post Link to post Share on other sites
happythoughts 0 #29 May 9, 2006 Quote1. If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? 4 hours Quote Share this post Link to post Share on other sites
tso-d_chris 0 #30 May 9, 2006 QuoteQuote1. If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? 4 hours (4*6)/(4+6) Quote Share this post Link to post Share on other sites
