A mixture of paint is prepared by mixing 1 part of red pigments with 8 parts of base. In the following table, find the parts of base that need to be added.
While mixing, the ratio of pigment and base should be the same.
As parts of pigment will increase, the parts of base will also increase.
Hence, it is a case of direct proportion.
We have red pigment to base ratio given as 1:8
Let part of base be x
(a) For red pigment equals to 4 :
⇒18=4x
⇒x=8×4=32
(b) For red pigment =7, :
⇒18=7x
⇒x=8×7=56
(c) For red pigment =12:
⇒18=12x
⇒x=8×12=96
(d) For red pigment =20:
⇒18=20x
⇒x=8×20=160