Expert: Richard J. Raridon - 2/6/2006

Question
Your with the following questions would be greatly appreciated, Thank you very much. mark

1.)Of 40L of an acid solution is 75% acid, how much pure acid is there in the mixture?

2.)A puzzle piece in the shape of a triangle has perimeter 30 cm. Two sides of the triangle are each twice as long as the shortest side. Find the length of the shortest side.

3.)On a vacation, Johnny averaged 50 mph traveling from Denver to Minneapolis. Returning by a different route that covered the same number of miles, he averaged 55 mph. What is the distance between the two cities if his total traveling time was 32 hr?

4.)Two planes leave Los Angeles at the same time. One heads south to San Diego; the other heads north to San Francisco plane flies 50 mph faster. In 1/2 hr, the planes are 275 mi apart. What are their speeds?

5.)Joe traveled against the wind in a small plane for 3 hr. The return trip with the wind took 2.8 hr. Find the speed of the wind if the speed of the plane in still air is 180 mph.  

Answer
1) 40(0.75) = 30L
2) let the sides be x, 2x and 2x so 5x=30, x = 6cm
3) time = distance/speed so 32 = x/50 +x/55 and x = 838 miles
4) let v = speed of slower plane
275 = v(0.5) +(v+50)(0.5) so v = 250mph
5) let s = speed of wind and x = distance traveled
3 = x/(180-s) and 2.8 = x/(180+s) so s = 6.2mph