1. y varies directly as x. If y = 16 when x = 4, find y when x = 5
2. y is directly proportional to x. If y =35 when x = 5, find y when x = 12
3. If y varies inversely as x and y is 12 when x = 5, find y when x = 3.
4. If z varies jointly as x and y, and z = 6 when x = 4 and y = 10, find z when x = 20 and
y = 8.
5. If z varies directly as x and inversely as y, and z = 9 when x = 6 and y = 2, find z
when x = 8 and y = 12.​