Percentage

[Apoorv16]

A mixture contains sand and gravel in the ratio 1:4 the sand has 20% impurity.If total mixture weighs 10 kg, how much impurity is there?
Ans-400gm

[Guest]

hey
okay so we know the ratio is
S:G
1:4
there are 5 parts in the above ratio (1+4) and we can put both the sand and gravel into fractions.
Sand = 1/5 while gravel = 4/5
Sand= 1/5
and it says the impurity is 20%
change 20 % into a fraction = 1/5
and find the impurity of (multiply) the sand= 1/5 x 1/5 = 1/25
10kgs= 10000grams
to find the impurity: 10000/25= 400grams
hope you get it!