If the mean of 3, 5, 8, k, 14 and 17 is 11, what is the value of k

From the top of a storey-buliding, the angle of depression of a mango on a tree 20m away from the base of the storey building is 68°. if the mango is 4.5 m above the ground, what is the height of the storey building to the nearest metre?

If cos x = - \(\frac{5}{13}\) where 180° < X < 270°, what is the value of tan x -sin x ?

Given that \(\frac{(3 - y)}{2x}\) = \(\frac{(6y + 7)}{(4x - 5)}\), find the value of x when y = 2