Class 6 Maths Ratio And Proportion Unitary Method

Unitary Method

The method in which we first find the value of one unit and then the value of the required number of units is called as the unitary method.

If the value of 4 pencils is Rs40, what is the value of one pencil?

Value of 4 pencils = Rs. 40

Value of 1 pencil = 40/4

= Rs.10

The value of one pencil is Rs.10. Now it is possible to calculate the price of any required number of units.

If we want to calculate the value of 100 pencils then:

Value of 1 pencil       = Rs.10

Value of 100 pencils = 10*10 = Rs.100

Following examples further explain this method.

Problem: If it has rained 276 mm in the last 3 days, how many cm of rain will fall in one full week (7 days)? Assume that the rain continues to fall at the same rate.

Solution:

Amount of rain in the last 3 days = 276mm

Amount of rain in 1 day = 276/3

Amount of rain in 1 day = 92 mm

Amount of rain in a week = Amount of rain in 7 days

Amount of rain in 7 days = 7*(Amount of rain in 1 day)

= 7*92

Amount of rain in 7 days = 644 mm.

Problem: A truck requires 108 litres of diesel for covering a distance of 594 km. How much diesel will be required by the truck to cover a distance of 1650 km?

Litres of diesel used in covering 594 km = 108 litres

Litres of diesel used in covering 1km      = 108/594

= 0.1818  litres

Litres of diesel required in covering 1650 kms

= 1650*(litres of diesel used to cover 1 km)

Litres of diesel required in covering 1650 kms = 1650*0.1818

= 299.97 litres.

= 300 litres (Apporx.)

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