When it's turned into the teacher.

Sandals.

311311222110

C. Steel.

Sound can travel in air at approximately 332 metres per second. Sound waves travel faster and more effectively in liquids than in air and travel even more effectively in solids. Sounds can travel at approximately 6000 metres per second in some solids and at a quarter of this speed in water.

The piano.

Turn the equation to 180 degrees (upside down)
16 = 8 + 8.

A (August)

20 days.

f the persons can do the work in 80 days, means the work requires the input of 80 man-days. If 2 such mens are engaged they will do the same work in 80 man-days/2 men = 40 days. If half the work needs to be completed it will be done in 40/2 = 20 days.

Water

Hole.

Grandfather or Grandmother.

S is daughter of P and sister of T. So, T is daughter of P.

Now, the sister of P is the daughter of M. This means that P is also the daughter of M. Clearly, T is the granddaughter of M.
So, M is the Grandfather or Grandmother of T.

Nine.