Ohama is landing a plane on the runway. He's trying to decide where he should deploy the plane's landing gear so that the plane comes to a stop exactly at the end of the runway. The runway is 600 yards long, and the plane will travel half the distance with the landing gear than without the landing gear. Where should he deploy the landing gear ?

Let's define:

A = distance traveled before deploying the landing gear

B = distance traveled after deploying the landing gear.

We must have that the sum of those two distances must be equal to 600 yards.

A + B = 600 yd.

And we know that:

" the plane will travel half the distance with the landing gear than without the landing gear."

Then we have that:

B = A/2.

Now we can replace this last equation in the first one:

A  + B = 600yd

A + A/2 = 600yd.

(3/2)*A = 600yd.

A = (2/3)*600yd = 400yd.

Ohama should deploy the landing gear 400 yd into the runway.