i) -25

as the distance given between window and ground is 25knots

you must be thinking why minus?

because if you consider a graph in mind below zero in y-axis all values starts in minus value and here window that is 0 is above the ground so we are going downward

hence -25 represent ground

ii) -14

we know that distance between ground and window is 25 and plant came upto 11 from ground hence it's tip will be on 25-11 that is 14

and again it will be minus because we are still below the window which equals 0

iii) -12

As we have given she climbs down 3 knots a minute it means she goes 12 knots in 4 minutes

but yet again we are going downward window which is 0 hence it will -12

Hope it helps and i gave you perfect reason too

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