Solve each problem involving direct variation.
1.) If y varies directly as x, and y = 16 when x = 5, find y when x = 10
2.) If y varies directly as x, and y = 14 when x = 3, find y when x= 6
3.) If y varies directly as x, and y = 3 when x = 18, find y when x = 9
4.) If y varies directly as x, and y = 15 when x = 9, find y when x = 3 ​