Find the value of z: 90/15 6/z

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

Parks is wearing several rubber bracelets one third of the bracelets are tie dye 1/6 are blue and 1/3 of the remainder are camouflage if park swears to camouflage bracelets how many bracelets does he have on

With finding limits of multi variable !