If y varies directly as x, and y is 20 when x is 4, whats this relation?

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

Two years ago a man was six times as old as his daughter. in 18 years he will be twice as old as his daughter. determine their present ages.

I’m really confused and need to learn this