Choose the correct answer. If y varies directly as x and inversely as z, and y = 25 when x = 5 and z = 3,...

3) Choose the correct answer.
If y varies directly as x and inversely as z, and y = 25 when x = 5 and z = 3, find y when x = 10 and z = 25.
4) Choose the correct answer.
If y varies jointly as x and z, and y = 8 when x = 12 and z = 4, find z when y = 5 and x = 7.