How many gallons of milk containing 1% fat is mixed with milk containing 4% fat to obtain a 15 gallon mixture containing 2% fat?

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

Aproduction manager test 10 toothbrushes and finds that their mean lifetime is 450 hours. she then design sales package of this type of toothbrush. it states that the customers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics

Ahiker stands at an unknown elevation before he ascends 2 miles up a mountain to an elevation of 9 miles. find the elevation of the hiker before his ascent.