Eric practiced piano an guitar for a total of 8 hours this week. he practiced the piano for 1/4 of that time. how many hours did eric practice the piano this week?

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?

What is the measure of sty in oo below? 130 310 230 50