Bunuel wrote:
If a teacher distributed 105 candies to 50 students in her class, how many students received only one candy?
(1) None of the students received more than three candies.
(2) Fifteen students received only two candies each
(1) a + b + c = 50 (total of students) and a + 2b + 3c = 105 (total of candies)
a = number of student that received 1 candies
b = number of student that received 2 candies
c = number of student that received 3 candies
Insufficient(2) number of student that received 2 candies is 15
InsufficientBoth together:
from (2): b = 15, then
a + b + c = 50
a + 15 + c = 50
a + c = 35
c = 35 - a
a + 2b + 3c = 105
a + 2*15 + 3*(35 - a) = 105
a + 30 + 105 - 3a = 105
2a = 30
a = 15; Since a is number of student that received 1 candies, so the answer is 15.
BOTH ARE SUFFICIENT