enigma123
In Washington School,
150 students study physics or biology or both. If 60 of these students do not study biology, how many of these students study both physics and biology?
(1) Of the 150 students, 40 do not study physics.
(2) A total of 110 of the students study physics.
I understand the rest of the question apart from the highlighted text. Can someone please try to explain where it fits in the table please? And also, I will appreciate if you can also please let me know how to get D as an answer.
In Washington School, 150 students study physics or biology or both. If 60 of these students do not study biology, how many of these students study both physics and biology?"150 students study physics or biology or both" means:
150={physics}+{biology}-{both}, we subtract {both} (students who study both physics or biology) since its counted in {physics} as well as in {biology}.
"60 of these students do not study biology" means:
60={physics}-{both} (so 60 study ONLY physics) -->
150=60+{biology} (from above) -->
{biology}=90.
Question:
{both}=?(1) Of the 150 students, 40 do not study physics -->
40={biology}-{both} -->
40=90-{both} -->
{both}=50. Sufficient.
(2) A total of 110 of the students study physics -->
{physics}=110, so from
60={physics}-{both} -->
{both}=50. Sufficient.
Answer: D.