Two fith grade sums, pls help me solve them....?

Question

A pool is 50 m long 25 m wide and 4 m deep, what will be the expenditure on cementing its walls and the floor at the rate of $25/m

A pool is 25 m long, 10 m wide and 3 m deep, what will be the cost of cementing its walls and floor @ $1250 per 100m

gimme total solution and the formula applied

thanx in advance

Answer 1

I'm going to go ahead and assume that the rates are for m^2 since it can't really be dealt with any other way.

Bottom of pool= 25m*50m

Sides of pool = 2(25m*4m)+2(50m*4m)

Total surface area= 1250+200+400= 1850m^2

1850m^2(25$/m^2)= $46,250

Bottom of pool = 25m*10m

Sides of pool = 2(25m*3m)+2(10m*3m)

Total surface area = 250+150+60

460m^2($1250/100m^2) = $5,750

Answer 2

1)

area of walls =(2x100+2x200).

area of floor =1250.

total area=200+400+1250=1850

total cost =1850x25$=46250$.

2)area of walls =(2x30+2x75).

area of floor =250.

total area=60+150+250=460

since the cost is 1250 per 100 sq.m

the cost per sq.m is 12.5$

and the total cost is 460x12.5=5750$

Answer 3

1st problem:

= $25([50 * 25] + 2[25 * 4] + 2[4 * 50])

= $25(1,250 + 2[100] + 2[200])

= $25(1,250 + 200 + 400)

= $25(1,850)

= $46,250

Answer: $46,250 for 1,850 sq meters surface area

= $1,250([{25 * 10} + 2{10 * 3} + 2{3 * 25}]/100)

= $1,250([250 + 2{30} + 2{75}]/100)

= $1,250([250 + 60 + 150]/100)

= $1,250(23/5)

= $5,750

Answer: $5,750

Answer 4

1. use the surface area of a rectangular prism formula to find the surface area but keep in mind that one side can be omitted because there is no cementing on the top

SA=2lh+2wh+lw

SA=2(50)(4)+2(25)(4)+(50)(25)

    =1850 m^2

multiply the SA by the rate to get 1850*25=$46 250

2. Same idea to find surface area

SA=2lh+2wh+lw

     =2(25)(3)+2(10)(3)+(25)(10)

     =460m^2

if the cost is $1250/100m^2, just divide to get the price per square metre

1250/100 = $12.50/m^2

Now multiply SA by rate again

460*12.50 = $5750