We bought a total of 90 books at the store. Math books cost $4 and history books cost $5. The total price was $396. How many math books did we buy?	Select.
A) 47  B) 54  C) 56  D) 61  E) 64
M + H = 90   H = 90 - M   4M + 5H = 396   4M + 5*(90 - M) = 396   M = 54   The answer is 54.
<result>B</result>
We bought a total of 90 books at the store. Math books cost $4 and history books cost $5. The total price was $396. How many math books did we buy?