translate the given information into a system of equations. the question is below

Question

to augment the collection of a small school library 7 books were acquired at the cost of php900. the new acquisition consists of mathematics and English books,each of which costs php150 and php100 respectively. how many mathematics and English books were acquired?

Answer 1

Two unknowns means two equations.

 

Let m = # of math books; let e = # of English books

 

eq # 1)  m + e = 7, so e = 7 - m

eq # 2)  150 m + 100 e = 900

 

Substitute: 150 m + 100 (7 - m) = 900

 

                 150m + 700 - 100m = 900

 

                 50m = 200

 

                 m = 4 and e = 3