LUANDATO wrote:A physics class has majors and non-majors in a ratio of 4 to 10. If two more majors were to be added to the class, the ratio would then be 2 to 4. How many people are in the class?
A. 14
B. 28
C. 42
D. 56
E. 70
We can PLUG IN THE ANSWERS, which present the total number of people in the class.
Let P = physics majors and N = non-physics majors.
When the correct answer is plugged in, adding 2 physics majors will yield the following ratio:
(New P)/N = 2/4 = 1/2.
B: total = 28
In this case:
Since P:N = 4:10 = 8:20, P=8 and N=20, with the result that the total number of students = 8+20 = 28.
After 2 physics majors are added -- increasing the value of P from 8 to 10 -- we get:
(new P)/N = 10/20 = 1/2.
Success!
The correct answer is
B.
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