let

p = the number of points that Paula scored

m = the number of points that Maria scored

paula scored twice as many points as maria:

p = 2m

the total number of points is 51:

p + m = 51

by solving the system of equations:

p = 2m

p + m = 51

we find:

p = 34 points

m = 17 points

click here to see the step by step solution of the system of equations:

Paula scored 34 points.

Maria scored 17 points.