Thursday, December 17, 2015

513: Compound Area

Can you come up with other, better, divisions?






source.

Wednesday, December 16, 2015

512: Factory Ratios 3

We started with this:
In a factory, the ratio of men to women is 2:3. The ratio of right-handed men to left-handed men is 7:3. The ratio of right-handed women to left-handed women is 11:1. What fraction of the factory workforce is right-handed?
And then we extended with: What is the fewest number of employees possible in this building?

If the ugly-sweater party was held in that factory with the minimum number of workers possible and the  ratio of red to green ugly sweaters was 7:13, how likely is it that a left-handed man wore a red ugly sweater?

Source:

511: Factory Ratios 2

We started with this:
In a factory, the ratio of men to women is 2:3.
The ratio of right-handed men to left-handed men is 7:3
The ratio of right-handed women to left-handed women is 11:1
What fraction of the factory workforce is right-handed?
But let's extend things a bit.

What is the fewest number of employees possible in this building?

Source:

510: Factory Ratios 1

In a factory, the ratio of men to women is 2:3.
The ratio of right-handed men to left-handed men is 7:3
The ratio of right-handed women to left-handed women is 11:1

What fraction of the factory workforce is right-handed?


Source:

Saturday, November 28, 2015

509: Circles 2

Several days ago, I posted a slightly different question about tangential circles and the spaces in between. Compare this question, from the 2004 SAT Practice Test to that question from Emma Bell.
  • Which question seems harder? What are the difficult aspects of each?
  • Do we have to specify the angle APB?
  • How are these two questions different in terms of the knowledge they require for solving?
  • Is this question made harder by the "how many times" part? Does that phrasing make the question unnatural?



source: ETS, 2004

508: Shorter Path


What car will have the shorter path?
How could you tell for certain?

source: Justin Aion

Sunday, November 22, 2015

507: Orderly Probability

Scenario 1: Which winning number group is more likely to occur?

1-2-3-4-5-6  OR 4-8-15-16-23-42

Scenario 2: Which winning number group is more likely to occur if the numbers are drawn in any order and THEN put into ascending order by the presenter?

1-2-3-4-5-6  OR 4-8-15-16-23-42

In which of the above two scenarios is getting the winning numbers more likely?

source: Jeff Suzuki