Ram got twice as many marks in English as in Science. His total mark in English, Science and Math are 180. If the ratio of his marks in English and Maths is 2 : 3, what is the marks in Science = ?

Let marks in English, Math and Science are E, M, S respectively
$$\eqalign{ & {\text{Given,}} \cr & {\text{2S}} = {\text{E}} \cr & {\text{S}}:{\text{E}} = 1:2 \cr & {\text{E}}:{\text{M}} = 2:3 \cr & {\text{S}}:{\text{E}}:{\text{M}} \cr & 1:2 \cr & \,\,\,\,\,\,\,\,\,2:3 \cr & \overline {1:2:3} \cr & {\text{Let }}x:2x:3x \cr & \therefore x + 2x + 3x = 180 \cr & \Rightarrow 6x = 180 \cr & \Rightarrow x = 30 \cr & {\text{Marks in Science}} \cr & = 1 \times 30 = 30 \cr & {\text{Marks in English}} \cr & = 2 \times 30 = 60 \cr & {\text{Marks in Maths}} \cr & = 3 \times 30 = 90 \cr} $$