But for this - what if all 180 members attend yoga, meaning 180 attend strength. This would mean the amount of members attending yoga would be equal to strength. A different scenario would be that 50 attend yoga, meaning 50 attend strength. If 30 more members attend strength only, this would now be 80 strength and 50 yoga, meaning that strength is greater than yoga. Thus we don't have a definitive answer for whether members attending yoga are greater than those attending strength.
Statement (2) says every yoga attendee also does strength training, meaning yoga ≤ strength always. So yoga can never be greater. The answer is definitively
. Statement (2) is sufficient.
GMAT Club Official Explanation:
Out of 180 gym members, is the number of members who attend yoga sessions greater than the number who attend strength training sessions?(1) Every member who attends yoga sessions also attends at least one other type of session.
This tells us that no one attends only yoga, but it doesn’t specify
which other session is attended. So:
Suppose 10 members attend yoga, and all of them also attend cardio. Strength training has 5 members. Then yoga > strength, so the answer is Yes.
Suppose 10 members attend yoga, and all of them also attend cardio. Strength training has 50 members. Then yoga < strength, so the answer is No.
Not sufficient.
(2) Every member who attends yoga sessions also attends strength training sessions.
This means the entire yoga group is included in the strength training group. So yoga cannot be greater than strength, giving a definite No answer to the question. Sufficient.
Answer: B.