Question

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

Answer 1

Answer:

1)

Cost of leveling

= 4.50 × (80 × 35)

= 4.50 × 2800

= ₹12,600

2)

Distance to walk = 3 × Perimeter

= 3 × [2×(80+35)]

= 6 × 115m

= 690 m

Time taken = 690/1.5

= 460 sec.

= 7 min. 40 sec.

Answer 2

Step-by-step explanation:

Simple

I) Since cost is given as 4.5 /m^2

The unit is m^2

Means find the area of the ground

That is (80 x 35) m^2

So

1 m^2 costs 4.50

The 80 x35 m^2 will cost = 4.50 x2800 =12600

ii) Perimeter is 2(l+b) = 2(80+35) =230 m

Three times = 3*230 =690

Means distance =690 m

And. Speed = 1.5m/s given

Time = distance /speed

=690/1.5 =460 m/s