Q. 633.7( 3 Votes )

# If x varies inversely as y and x = 20 when y = 600, find y when x = 400.

Answer :

If x varies inversely as y.

∴ xy = k(constant) …(i)

If x = 20 and y = 600

∴xy = 20× 600 = 12000

⇒ k = 12000

When x = 400, then from Eq. (i)

y× 400 = k

⇒ y × 400 = 12000

⇒

Rate this question :

A car travels a distance of 225 km in 25 litres of petrol. How many litres of petrol will be required to cover a distance of 540 kilometres by this car?

NCERT - Mathematics ExemplarTruck needs 54 litres of diesel for covering a distance of 297 km. The diesel required by the truck to cover a distance of 550 km is

NCERT - Mathematics ExemplarIn which of the following case, do the quantities vary directly with each other?

NCERT - Mathematics ExemplarThe variable x is inversely proportional to y. If x increases by p%, then by what percent will y decrease?

NCERT - Mathematics ExemplarA bowler throws a cricket ball at a speed of 120 km/h. How long does this ball take to travel a distance of 20 metres to reach the batsman?

NCERT - Mathematics ExemplarThe following table shows the distance travelled by one of the new eco-friendly energy-efficient cars travelled on gas.

Which type of properties are indicated by the table? How much distance will be covered by the car in 8 litres of gas?

NCERT - Mathematics ExemplarMs. Anita has to drive from Jhareda to Ganwari. She measures a distance of 3.5 cm between these villages on the map. What is the actual distance between the villages if the map scale is 1 cm = 10 km?

NCERT - Mathematics Exemplar