Question

Jim makes a mixture which contains 10 mg of salt, 30 mg of sand, and some iron filings. The total mass of the mixture is 100 mg
Which amount of iron filings does Jim use in the mixture?
A10
B30
C40
D60
​

Answer 1

Answer:

Amount of iron fillings in mixture = 60 mg

Explanation:

Given:

Total mass of mixture = 100 mg

Amount of salt in mixture = 10 mg

Amount of sand in mixture = 30 mg

Find:

Amount of iron fillings in mixture

Computation:

Using Law of Conservation of mass;

Total mass of mixture = Amount of salt in mixture + Amount of sand in mixture + Amount of iron fillings in mixture

100 = 10 + 30 + Amount of iron fillings in mixture

100 = 40 + Amount of iron fillings in mixture

Amount of iron fillings in mixture = 100 - 40

Amount of iron fillings in mixture = 60 mg