In a certain calculus class, the ration of the number of mathematics majors to the number of students who are not mathematics majors is 2 to 5. If 2 more mathematics majors were to enter the class, the ratio would be 1 to 2. How many students are in te class?
A) 10
B) 12
C) 21
D) 28
E) 35
解答FROM og:
m - number of math majors and n - be the number of nonmath majors in the class.
m/n = 2/5
If the numberof math majors is increased by 2
m+2/ n = 1/2
** 我的問題是 為何加了兩個數學主修學生之後, 總數還是n ? 而不是n+2?
~thanks~
