SOLUTION: hi, i find these question's extremley difficult.....so can you plzz show me how to solve these questions....thanks 1) A chemist mixes a 20% solution and a 50% solution to obta

Question 202289: hi, i find these question's extremley difficult.....so can you plzz show me how to solve these questions....thanks

1) A chemist mixes a 20% solution and a 50% solution to obtain a 40% solution. If 300g of solution was obtained, how much of each type of the original solutions were used?
2)It took Terry 7 hours to drive the 390 km from Cold Bay to Hot Lake. For the first part of the trip he averaged 60 km/h, but was forced to slow down for the remainder of the trip to 50km/h.
(a) How many hours did Terry spend driving at each speed?
3)How can you tell by looking at an equation whether it has one, none or infinite solutions?
Answer by rfer(16322) (Show Source): You can put this solution on YOUR website!
A)
.2x+.5(300-x)=.4(300)
.2x+150-.5x=120
-.3x=-30
x=100
20% solution =100 g
50% solution =300-100=200g
B)
4 hrs at 60
3 hrs at 50
see if you can put the equation together
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