Q. 61

# A recipe calls for 1 cup of milk for every cups of flour to make a cake that would feed 6 persons. How many cups of both flour and milk will be needed to make a similar cake for 8 people?

Answer :

The ratio of number of cups of milk to number of people is constant

When number of cups of milk = 1 number of people are 6

⇒ ratio = = …(i)

When number of people are 8 let number of cups of milk required be ‘a’

⇒ ratio = =

Using (i)

⇒ =

Cross multiply

⇒ a =

Divide numerator and denominator by 2 we get

⇒ a = = = +

⇒ a = 1 + = 1 cups of milk

The ratio number of cups of milk to number of cups of flour is constant

When number of cups of milk is 1 number of cups of flour =

⇒ ratio = = = …(ii)

Let number of cups of flour required be ‘b’ when number of cups of milk are

⇒ ratio = = =

Using (ii)

⇒ =

Cross multiply

⇒ 3b × 2 = 4 × 5

⇒ b =

Divide numerator and denominator by 2

⇒ b = = = +

⇒ b = 3 cups of flour

Therefore, cups of milk needed to make cake for 8 people is 1 and that of flour is 3

Rate this question :

There are ‘b’ boys and ‘g’ girls in a class. The ratio of the number of boys to the total number of students in the class is:

NCERT - Exemplar MathematicsFind the ratio of the following:

(a) 30 minutes to 1.5 hours

(b) 40 cm to 1.5 m

(c) 55 paise to Rs 1

(d) 500 ml to 2 litres

NCERT - MathematicsFill in the following blanks:

[Are these equivalent ratios?]

NCERT - MathematicsDistances travelled by Hamid and Akhtar in an hour are 9 km and 12 km. Find the ratio of the speed of Hamid to the speed of Akhtar.

NCERT - Mathematics