The graph shows the proportional relationship between time, in minutes, spent skateboarding and the number of calories burned.

Graph with x axis labeled time minutes and y axis labeled calories burned. A line begins at point 0 comma 0 and goes through points 15 comma 150 and 30 comma 300.

Write an equation that represents the relationship.

y = 50x
y = 10x
y equals 1 over 50 times x
y equals one tenth times x

help me help me!