Question

Sharifah arranges Mathematics, Science and History reference books on a bookshelf. Given the total number of

reference books is 3 times the number of Science reference books. The number of Science reference books is 6 less
than the Mathematics reference books. Express the number of History reference books in the form of an algebraic
expression.

Answer 1

Explanation:

m = number of math books

s = number of science books

h = number of history books

m + h + s = 3s

m + h = 2s

s = m - 6

m + h = 2(m - 6) = 2m - 12

h = m - 12

and since s = m - 6, this also means

h = s - 6

that means, the number of History reference books is 12 less than the Mathematics reference books. which is then 6 less than the number of Science reference books.