a rectangular pit 1 4 long,90cm broad and 70cm deep was dug and 1000 bricks each of base 21cm by10 - Maths -

Question

a rectangular pit 1 4 long,90cm broad and 70cm deep was dug and
1000 bricks each of base 21cm by10 5cm were made from the earth dug
out find the height of each brick
2 how many wooden cubes of an edge 25cm in length can be cut out
from a cuboidal log of size 2 5mby 0 5m by 50cm assuming that there
is no wastage
3 a closed box is made up of 2cm thick wood with external
dimention 84x75x64cm find the volume of the wood required to make
the box
4 a swimming pool is 50m length ,30m in breadth and 2 5m in
depth find the cost of cementing its floor and walls at the rate of
rs 27per square metre
5 the floor of a rectangular hall has a perimeter 236,its height
is 4 5m, find the cost of painting its four walls(doors and windows
be ignored) at the rate of rs 8 40 per square metre
6 a cuboidal fish tank has a length of 30cm, a breadth of 20cm
and a height of 20 cm, the tank is placed on a horizontal table and
it is three quarters full of water, find the area of the tank which
is in contact with water
7a box of nutties has a ribbon tied as 12cmby 18cm by 30cm with
32 cm for a bow what length of ribbon was used

priyanka saggu · Accepted Answer

2 Dimensions of cuboid:l = 2 5 m = 250 cm ; b = 0 5 m = 50 cm and h
= 50 cmEdge of cube : 25 cmAs n number of cubes can be cut
from the cuboid so the volume of these cubes = volume of
cuboidn×volume of a cube = volume of cuboidn = volume of
cuboidvolume of cuben = 250
×50×5025×25×25
n = 62500015625= 40So, the number of cubes can be cut from cuboid
is 40

4 Dimensions of swimming pool:l = 50 m ; b = 30 m ; depth (h) = 2 5
mArea of four walla and floor = area of five faces = 2(l + b) h +
l×bPut the values,=2(50 + 30)×2 5 +
50×30=2×80×2 5 + 1500=400 + 1500 = 1900 m2
Now the cost of cementing it at the rate of Rs 27 per square metre
= 1900 ×27=Rs 51,300