JEE Advanced Model Paper 8 with solutions for online practice

The quadrilateral formed by the lines y = ax + c, y = ax + d, y = bx + c and y = bx + d has area18. The quadrilateral formed by the lines y = ax + c, y = ax + d, y = bx + c and y = bx + d hasarea 72. If a, b,c,d are positive integers then the least possible value of the sum a + b + c + d is