Assume the statements are true.
Statements: Some shells are pebbles. All pebbles are marbles.
Conclusions:
I. All shells are marbles.
II. Some marbles are shells.

Only I followsCorrect answerYour answerOnly II followsCorrect answerYour answerNeither I nor II followsCorrect answerYour answerBoth I and II followCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

The shells that are pebbles are marbles. So some shells are marbles, and reversing, some marbles are shells: II follows.
Only some shells are known to be pebbles; the other shells need not be marbles. I is not definite.
Only II follows.

Worth noting

Some + All gives only a Some conclusion. Upgrading it to All is the commonest slip.

Concept: Some + All gives Some, not All
Typical timeTypical: 40 s
Your timeYours: —

The rule this testsTwo statements

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Assume the statements are true.Statements: Some shells are pebbles. All pebbles are marbles.Conclusions:I. All shells are marbles.II. Some marbles are shells.

Explanation

Assume the statements are true.
Statements: Some shells are pebbles. All pebbles are marbles.
Conclusions:
I. All shells are marbles.
II. Some marbles are shells.