Yahoo Answers: Answers and Comments for Solving Applied Problems: Two Equations? [Mathematics]
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From Kate
enUS
Sun, 19 May 2013 14:40:59 +0000
3
Yahoo Answers: Answers and Comments for Solving Applied Problems: Two Equations? [Mathematics]
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https://answers.yahoo.com/question/index?qid=20130519144059AA3gCC0
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From ranjankar: Let the no of " 60 seconds " commer...
https://answers.yahoo.com/question/index?qid=20130519144059AA3gCC0
https://answers.yahoo.com/question/index?qid=20130519144059AA3gCC0
Mon, 20 May 2013 00:01:20 +0000
Let the no of " 60 seconds " commercial be x
Then the no of "30 seconds " commercial will be 12  x
Total commercial time = 60x + 30 (12x) = 10*60
60x +360  30x = 600
30x = 240
x = 8
ANSWER 8 commercials ( 60 seconds) AND 4 commercials ( 30 seconds)
CHECK
8X 60 = 480
4X 30 = 120
ADD = 600 seconds = 10 minutes
2) Let the quantity of 50% acid mixed be x liters
Then the quantity of 25% acid mixed will be (10  x) liters
0.50x + 0.25 ( 10x) = 0.40*10
0.50x + 2.50  0.25x = 4
0.25x = 1.50
x = 6
ANSWER 6 liters (50%) and 4 liters (25%)
CHECK
0.50 X 6 = 3
0.25 X 4 = 1
ADD 4
4/10 X 100 = 40%
3) Let the speed of Darren's canoe in still water be x km/ hour
Speed of current = 6km/ hour
DOWNSTREAM

Speed = ( x+6) km/ hour
Distance traveled = Speed X time
= ( x+6) X 4 = 4x +24 km
UPSTREAM

Speed = ( x6) km/ hour
Distance = 10 ( x6) = 10x 60 km
DISTANCE TRAVELED EACH WAY IS SAME
10x  60 = 4x + 24
6x = 84
x = 14
ANSWER 14km/ hour
CHECK
4 ( 14+6) = 80km
10 ( 146) = 80km