In question 2 above (A mixture of paint is prepared by mixing 1 part of red pigments with 8 parts of base.), if 1 part of red pigment requires 75 ml of base, how much red pigment should we mix with 1800 ml of base?
Let the number of parts of red pigment be x and the parts of base be y.
As the number of parts of red pigment increases, the amount of base also increases in the same ratio. So they are in direct proportion.
Two numbers x and y are said in direct proportion if, the relationship between two quantities is such that if we increase one, the other will also increase, and if we decrease one the other quantity will also decrease.
x/y = k, x = ky
where k is a constant.
Thus, x₁ / y₁ = x₂ / y₂
x₁ = 1, x₂ = ?
y₁ = 75, y₂ = 1800
1 / 75 = x₂ / 1800
x₂ = 1 × 1800 / 75
x₂ = 24
Thus, 24 parts of red pigment should be mixed with 1800 ml of base.
In question (2), above if 1 part of red pigment requires 75 ml of base, how much red pigment should we mix with 1800 ml of base?
NCERT Solutions Class 8 Maths Chapter 13 Exercise 13.1 Question 3
In question (2), above if 1 part of red pigment requires 75 ml of base, 24 parts of red pigment should be mixed with 1800 ml of base.
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