Necessary Assumption Drill Pack
10 original LSAT-style questions. Work at your own pace. Answer key on the last page.
The new highway bypass will cut commute times, because drivers will be able to avoid the congested downtown corridor.
The argument assumes that
- A. drivers know about the bypass
- B. the bypass will not become as congested as downtown
- C. commute times are currently too long
- D. the bypass is scenic
- E. downtown businesses support the bypass
Answer: ______
Organic vegetables must be healthier, because they are grown without synthetic pesticides.
The reasoning depends on the assumption that
- A. organic vegetables taste better
- B. synthetic pesticides are harmful to health
- C. organic farming is more expensive
- D. all vegetables contain some pesticides
- E. consumers prefer organic labels
Answer: ______
The software upgrade will save the company money, since it automates the invoicing process.
Which of the following is an assumption required by the argument?
- A. Employees like the new software.
- B. The cost of the upgrade is less than the labor savings from automation.
- C. Invoicing is currently done by hand.
- D. The company sends many invoices.
- E. Automation always saves money.
Answer: ______
The city plans to reduce traffic by adding a lane to the highway. Officials say the extra capacity will let the same number of cars move faster.
Which of the following is an assumption on which the officials' plan depends?
- A. Building the lane will not take more than a year.
- B. The number of cars using the highway will not increase because of the new lane.
- C. Drivers prefer highways to side streets.
- D. The highway is the busiest road in the city.
- E. Other cities have reduced traffic this way.
Answer: ______
The new subway line will pay for itself within ten years, because fare revenue is projected to cover construction costs by then.
The argument assumes that
- A. the subway line will be popular with commuters
- B. construction will be completed on schedule
- C. operating and maintenance costs will not exceed fare revenue in a way that blocks repayment
- D. fares will never increase
- E. other cities' subway lines paid for themselves
Answer: ______
Switching the office to a four-day week will not hurt output, because employees will work the same total hours compressed into four days.
The argument depends on the assumption that
- A. employees prefer a four-day week
- B. working longer days does not reduce hourly productivity
- C. clients will not notice the change
- D. the office will stay open on Fridays
- E. output is currently too high
Answer: ______
The airline's new baggage fee will increase profits, since passengers will keep checking bags at the same rate.
The argument assumes that
- A. passengers dislike baggage fees
- B. the fee will not cause enough passengers to switch airlines to erase the gain
- C. other airlines charge baggage fees
- D. profits are currently low
- E. baggage handling is expensive
Answer: ______
The museum's new exhibit will draw record crowds because it features the famous Blue Diamond.
The argument assumes that
- A. the Blue Diamond is valuable
- B. people will know the Blue Diamond is on display
- C. the museum has advertised before
- D. record crowds are good for the museum
- E. other exhibits were less popular
Answer: ______
The new bridge will reduce traffic because drivers will use it instead of the old road.
The argument assumes that
- A. the bridge is long
- B. enough drivers will switch to the bridge to make a difference
- C. bridges are expensive
- D. the old road will close
- E. drivers like new bridges
Answer: ______
Lowering the speed limit will save lives, because higher speeds make crashes deadlier.
The argument depends on the assumption that
- A. drivers obey speed limits
- B. crashes currently happen
- C. lowering the limit will actually reduce driving speeds
- D. speed limits are currently too high
- E. police enforce speed limits
Answer: ______
Answer Key
- 1. B — If the conclusion is true, and the bypass will cut commute times, then the bypass has to stay clearer than downtown. A bypass as clogged as downtown saves nobody any time. B has to be true.
- 2. B — Avoiding synthetic pesticides only matters for health if those pesticides are harmful. If the conclusion is true, and organic vegetables are healthier, then synthetic pesticides have to be harmful to health. B has to be true.
- 3. B — Automation only saves money overall if the upgrade costs less than what it replaces. A pricey upgrade could cost more than the labor it saves.
- 4. B — If the conclusion is true, and the same number of cars will move faster, then the number of cars has to stay the same. A new lane that draws more cars breaks the claim. B states what has to be true.
- 5. C — Fare revenue can only cover construction if it is not eaten up by operating costs first. If maintenance swallows the revenue, the line never pays for itself.
- 6. B — Same total hours only means same output if each hour is as productive. If longer days tire people out, output drops even with equal hours.
- 7. B — The fee only raises profits if it does not drive customers away. If passengers defect to rivals, the "same rate" premise collapses.
- 8. B — If the conclusion is true, and the exhibit will draw record crowds, then people have to know the Blue Diamond is on display. A famous artifact draws nobody if nobody hears it is there. B has to be true.
- 9. B — If only a few drivers switch, traffic barely changes. The conclusion needs a meaningful number of switchers.
- 10. C — A lower limit only saves lives if speeds actually fall. If everyone keeps speeding, the deadliness of crashes never changes.
Keep going: Necessary Assumption sample questions · How to answer necessary assumption questions