Quantcast XP Math - Forums - View Single Post - i need some math help for this boy that i'm babysitting right now...?
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Old 07-24-2007   #8
037 G
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Part 1. Here you have to combine using logic, common sense, and a little math you will get: if you drive 45 for six hours you have gone 45x6= 270 miles. So your total trip is 270 miles long.Now if you drive for 2 hrs at 53 mph you will have completed the first 106 miles (53x2) of the same 270 mile trip leaving 164 miles to be driven to complete this trip (270-106=164)Next the question becomes how fast do you have to drive to complete a 164 mile trip in 4 hrs (164/4=41) so you would have to drive 41mph to complete the remaining 164 miles in 4 hrs after doing the first 106 miles in 2 hrs at 53 mph. hope this helps for the first question.Part 2. Jonathan spent 1.9667hrs driving to the beach on the first day (118/60= 1.9667, I suspect you have a typo and ment to say 180km in which case the answer is 3hrs from 180/60) anyway, the next day he drives 1.638 hrs from (118/72 = 1.638 with the typo it is 180/72= 2.5 hrs) either way you add the hrs from both days to get the total. 1.9667+1.638=3.6047 hrs but I think it is more likely to be 3+2.5=5.5 hrs if the beach were 180 km away.Part 3. Destiny drove 39mi at 51mph so she drove for 0.764 hrs(time= distance/ speed = 39/51= 0.764 hrs), Now .764 hrs is approximately 46 minutes (.764x60=45.8823) so 46 minutes before 2:58 PM the time was 2:12 PM that is when she left.