A student gets an aggregate of 60% marks in five subjects in the ratio 10 : 9 : 8 : 7 : 6. If the passing marks are 50% of the maximum marks and each subject has the same maximum marks, in how many subjects did he pass the examination?

Let's say he scored marks as $$10x,9x,8x,7x,6x$$ or total of $$40x$$ which is 60% of total maximum marks(T).

$$\frac{T \times 60}{100}=40x$$

So T (total maximum marks)=$$\frac{400x}{6}$$

Or Individual max. marks = $$\frac{T}{5}=\frac{80x}{6}$$

Passing marks =50% of individual max. marks =$$\frac{40x}{6}=6.66x$$

Hence he scored more than passing marks in four subjects as $$10x,9x,8x$$ and $$7x$$

and failed in one subject as scoring $$6x$$ marks which is less than passing marks of $$6.66x$$