Question

The length and width of a playground is 80 m and 35 m respectively.
(1) Find the cost of levelling, it at 4.50 per square meter?
(ii) How long will a boy take to go three times round the field, if he walks at the rate of 1.5m per second?​

Answer 1

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given :-

length of the play ground = 80m

breadth of the play ground = 35m

area of the playground = Length × breadth

= 90 × 35

= 3150m²

now it's given that the cost of levelling is 4.50 per m².

therefore total cost of levelling = 4.50 × 3150

= 14175 rupees.

second part..

we have to find out the time taken by the boy if he goes around the playground three times @ 1.5 second per meter.

first of all, we have to find it's perimeter

perimeter of the playground = 2 ( l + b )

= 2 ( 80 + 35 )

= 2 × 115

= 230m

therefore total distance travelled by the boy = 230 × 3 ( since he goes around the playground 3 times )

= 690m

total time Taken = 690 × 1.5

= 1035 seconds

in minutes = 1035/60 ( one minute = 60 seconds )

= 17.25 minutes

Answer 2

Step-by-step explanation:

Length of play ground= 80m

Width of play ground= 35m

i) For levelling we need to find the area.

area of the playground= length*breadth6900

= 80*35

= 2800m²

For 1 m² cost of levelling= ₹4.50

For 2800 m² cost of levelling= ₹(4.50*2800)

= ₹12600

ii) The boy goes around the field.

So we need to find the perimeter here.

Perimeter of the playground= 2(length+breadth)

= 2( 80+35)

= 2* 115

= 230m

If he goes 3 times around the field, total distance covered= 230*3

= 690m

Now, For 1.5 m the boy takes 1 second

For 1 m the boy takes= 1/ 1.5 seconds

For 690 m he would take = 1/ 1.5 * 690

= 6900/1.5

= 4600 seconds

Therefore the cost of levelling the playground will be Rs. 12600 at the rate of 4.50 per m² and it would take 4600 seconds for a boy walking at 1.5 m/ s to go around the playground 3 times.

Hope this helps...