AB, CD and EF are three parallel lines, in that order. Let d1 and d2 be the distances from CD to AB and EF respectively. d1 and d2 are integers, where d1 : d2 = 2 : 1. P is a point on AB, Q and S are points on CD and R is a point on EF. If the area of the quadrilateral PQRS is 30 square units, what is the value of QR when value of SR is the least?
Area of the quadrilateral PQRS = 30
½2xy + ½xy = 30
xy = 20
So, for x yo be minimum, it should be 1.
∴ y = 20
So, QR = √(x2 + y2)
QR = √(202 + 12) = √401
which is slightly greater than 20.
The correct option is E.