Area ratio of parallelogram and two triangles

The quadrangle ABCD in a figure is a parallelogram. QS and BC are parallel and RT and CD are also parallel.

The point P which is an intersection of QS and RT is on the diagonal line BD.

(The length of BP) : (length of PD) = 2 : 1.

Find the area ratio between the sum of the area of the triangle AQT and CSR and the area of parallelogram ABCD.

Answer