Two observes p and q,15m apart obeserve a kite(a).In the same vertical plane and from the same side of kite.If the angle of elevation of the kite from p and q are 35 degrees and 45 degrees respectively.Find the kite correct to the nearest metre

you need to do better proofreading.

Assuming you want the height h of the kite,
draw a diagram and review your basic trig functions.
You can easily see that
h cot35° - h cot45° = 15