z varies jointly as x and y and z = 60 when x = 5 and y = 6. Find y when z = 80 and x = 4
PLEASE HELP ME​


Sagot :

z = kxy

60 = (k) (5) (6)

60 = 30k

k = 2

z = kxy

80 = (2)(4)(y)

80 = 8y

y = 10