Logical ReasoningDifficulty: Medium

PT3 S4 Q12 Explanation

The more television children watch

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsNecessary Assumption

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Stimulus

The more television children watch, the less competent they are in mathematical knowledge. More than a third of children in the United States watch television for more than five hours a day; in South Korea the figure is only 7 percent. But whereas less than 15 percent of children in the United States children are to do well in mathematics, they must watch less television.

What this question is testing

Necessary Assumption

Conclusion

The author looks at the U.S. vs. South Korea comparison and concludes: U.S. kids must cut back on TV to do well in math.

Evidence

U.S. kids watch more TV; U.S. kids know less advanced math. So TV must be the cause.

Evaluate

That logic only holds if TV is the relevant difference between the two countries. Compare two students from different schools — one struggles in math, one excels. Sure, one watches more TV. But maybe the schools also differ in how well they teach math. If that's true, the TV thing might not matter at all. The author quietly assumes the schools are roughly equal.

Goal

The right answer will rule out the obvious alternative cause: that the U.S. is just teaching this material substantially worse than South Korea is.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
12.

Which one of the following is an assumption upon which the

Answer choices

  1. Bad Assumption1% picked this

    Children in the United States are less interested in advanced measurement and geometric concepts than

    The author doesn't rely on a claim about interest. The argument is about TV-watching as the cause of the math gap. Negation test: even if U.S. children are equally interested in math, the argument that TV reduction is necessary still goes through, since the argument is about TV's effect on competence, not motivation. Not necessary.

  2. Bad Assumption2% picked this

    South Korean children are more disciplined about doing schoolwork than are children in

    The author doesn't need a discipline comparison either. Negation test: even if South Korean kids are no more disciplined than U.S. kids, the argument still concludes that given the negative effect of TV, U.S. kids must watch less. The argument is about TV's effect, not about discipline. Not necessary.

  3. Reversal / Negation10% picked this

    Children who want to do well in advanced measurement and geometry will

    This reverses the argument's direction. The author's claim is that less TV is necessary for doing well in math, not that wanting to do well in math causes less TV. Negation test: even if many kids who want to do well still watch lots of TV, the argument can still go through — the author would just say those kids are sabotaging themselves. Not necessary.

  4. Too Strong11% picked this

    A child’s ability in advanced measurement and geometry increases if he or she watches less than one hour

    The conclusion only requires that less TV would help. This answer makes a much stronger claim — that watching less than one hour a day increases ability. Negation test: even if no specific one-hour threshold exists, the conclusion that U.S. kids need to watch less TV could still hold (any reduction might help). Not necessary.

  5. Correct76% picked this

    The instruction in advanced measurement and geometric concepts available to children in the United States is not substantially worse than that

    Why this is right

    This rules out the major alternative explanation. The author uses the U.S./South Korea comparison to blame TV for the math gap, but the comparison only supports that conclusion if instructional quality is roughly comparable. Negation test: suppose U.S. instruction in advanced measurement and geometry is substantially worse than South Korea's. Then the math gap could be explained entirely by instruction, not TV — and reducing TV might not help at all. The conclusion that less TV is necessary collapses. So this assumption is necessary.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

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