Question

Water level in a well was 20 m below ground level. During rainy season, rain water collected in different water tanks was drained into the well and the water level rises 5 m above the previous level. The wall of the well is 1 m 20 cm high and a pulley is fixed at a height of 80 cm. Raghu wants to draw water from the well. The minimum length of the rope that he can use is ______.

Options

• 17 m

• 18 m

• 96 m

• 97 m

Answer 1

Water level in a well was 20 m below ground level. During rainy season, rain water collected in different water tanks was drained into the well and the water level rises 5 m above the previous level. The wall of the well is 1 m 20 cm high and a pulley is fixed at a height of 80 cm. Raghu wants to draw water from the well. The minimum length of the rope that he can use is 17 m.

Explanation:

Height of the wall of the well = 1 m 20 cm = 1.20 m

Height of the pulley = 80 cm = 0.80 m

∴ Required minimum length of the rope

= (20 – 5 + 1.20 + 0.80) m

= (15 + 2) m

= 17 m