If most of the off-cuts are also used then you will need 315 slabs. Otherwise you will need a lot more.
Depends on the linear dimensions of both the slabs and the ground.
The answer will vary slightly depending on assumptions: will the slabs have a space between them, and will you be cutting the slabs to fill fractions. 21 feet is equal to 14.2 of the 450 mm slabs. 19 feet is equal to 12.9 of the slabs. To complete the rectangular area, 14.2 x 12.9 = 183 slabs.
14
You will need 63 44cm x 44cm slabs to cover that area.
Joe needs 460 paving slabs to surrond the pond.
Generally speaking, masonry joints are typically ground out to at least a depth of 3/4". If your mortar is unuaually soft or loose you may need to go deeper.
Mix water with the mortar mix until it is a paste-like consistency. Then dip some of the mortar mix out with a hand trowel and turn the trowel upside down. If the mortar clings to the trowel blade, the mixture is perfect.
For every block, you will use approximately 1.2 pounds of mortar
1m2 of half brickwall required around 0.03m3 cement mortar
Yes, but you need to scrape or chip off as much of the old mortar as you can - both from the back of the tile and from the floor, just enough to ensure that the tile will set level.
400 at least