Question

a rectangular field is 90 metre by 70 metre. a man walks around it the rate of 4 kilometre per hour. what time all he take in making 5 rounds?

Answer 1

The perimeter is:

+P+=+2%2A90+%2B+2%2A70+

+P+=+180+%2B+140+

+P+=+320+ m

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His speed is:

+4000+ m/hr

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5 rounds is:

+5%2A320+=+1600+ m

--------------------

+d+=+r%2At+

+t+=+d%2Fr+

+t+=+1600+%2F+4000+

+t+=+.4+ hrs

Convert to minutes:

4.60=24

He takes 24 min to make 5 rounds