The boundary of a park about …

Running Exercise The doctor has told Devi Prasad to run 2 km every day to stay fit. He took one round of this field. How far did he run? The field was very far from his home. So he chose a park nearby. The boundary of the park was about 400 metres long. • How many rounds of the park must Devi Prasad run to complete 2 km? • One day the weather was very good and a cool breeze was blowing. He felt so good that he kept jogging till he got tired after 8 rounds. That day he ran _ _ __ km and _ _ _ metres ! Answer: • Devi Prasad took 1 round of the square field whose each side was 500 m long. Distance covered to take 1 round of the field = (500 + 500 + 500 + 500) m = 2000 m We know 1000 m = 1 km Thus, 2000 m = 2 km So, Devi Prasad ran 2 km to take one round of the field as advised by the doctor. Length of the boundary of the park = 400 m Number of rounds of the park taken by Devi Prasad to run 400 m = 1 Number of rounds of the park taken by Devi Prasad to run 1 m = 1400Number of rounds of the park taken by Devi Prasad to run 2000 m = 1400× 2000 = 2000 ÷ 400 = 5 We know 2000 m = 2 km So, Devi Prasad must take 5 rounds in order to complete 2 km. • Distance covered by Devi Prasad to take 1 round of the park = 400 m ∴ Distance covered by Devi Prasad to take 8 rounds of the park = 400 m × 8 = 3200 m We know 1000 m = 1 km ∴ 3200 m = 3000 m + 200 m 3200 m = 3 km + 200 m 3200 m = 3 km 200 m Thus, Devi Prasad ran 3 km 200 m to take 8 rounds of the park.

: Running Exercise The doctor has told Devi Prasad to run 2 km every day to stay fit. He took one round of this field. How far did he run? The field was very far from his home. So he chose a park nearby. The boundary of the park was about 400 metres long.

• How many rounds of the park must Devi Prasad run to complete 2 km?

• One day the weather was very good and a cool breeze was blowing. He felt so good that he kept jogging till he got tired after 8 rounds. That day he ran _ _ __ km and _ _ _ metres !

Answer:
• Devi Prasad took 1 round of the square field whose each side was 500 m long. Distance covered to take 1 round of the field = (500 + 500 + 500 + 500) m = 2000 m We know 1000 m = 1 km Thus, 2000 m = 2 km So, Devi Prasad ran 2 km to take one round of the field as advised by the doctor. Length of the boundary of the park = 400 m Number of rounds of the park taken by Devi Prasad to run 400 m = 1 Number of rounds of the park taken by Devi Prasad to run 1 m = 1400Number of rounds of the park taken by Devi Prasad to run 2000 m = 1400× 2000 = 2000 ÷ 400 = 5 We know 2000 m = 2 km So, Devi Prasad must take 5 rounds in order to complete 2 km.

• Distance covered by Devi Prasad to take 1 round of the park = 400 m ∴ Distance covered by Devi Prasad to take 8 rounds of the park = 400 m × 8 = 3200 m We know 1000 m = 1 km ∴ 3200 m = 3000 m + 200 m 3200 m = 3 km + 200 m 3200 m = 3 km 200 m Thus, Devi Prasad ran 3 km 200 m to take 8 rounds of the park.