SOLUTION: 1.The sum of two numbers is 143 and the difference is 7 what are the numbers? 2.There are 10 boxes five contain pencils and four contain pens and two contain pens and pencils. How
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Question 1084551: 1.The sum of two numbers is 143 and the difference is 7 what are the numbers? 2.There are 10 boxes five contain pencils and four contain pens and two contain pens and pencils. How many boxes contain no pens and pencils. 3.A car travelling at an average speed of 100km/h covers a certain distance in 3hours.At what average speed must the car travel to cover the same distance in 2hours? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! x+y=143
x-y=7
2x=150
x=75
y=68
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P(pen or pencil)=P(pen)+p(pencil)-p(both pen and pencil)
or=5+4-2=7 (the minus two is the double counting)
7 contain one or the other
therefore 3 don't contain any.
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at 100km/h average speed*3 hours is 300 km distance
to do it in 2 hours requires 300 km/2 hr or 150 km/hr.
