Sunday, November 23, 2014

320: Sensible or Not? percent

Percent Statements: Sensible or Not?
Defend your answer! Here's your claim ... what's your warrant?
  1. The percentage of households with more than four children decreased by 100,000 households
  2. Brent makes 120% less than Bill each month 
  3. Ann is 10% taller than Brenda, so Brenda is 10% shorter than Ann
  4. Fifty percent of the people in the room are men and 50% of the people in the room are single. Therefore, 25% of the people in the room are single men.
  5. Pete’s prices are 10% more than Paul’s prices, so Pete’s prices are 110% of Paul’s prices.
  6. The interest rate at the bank increased by 100% 
ch2.3

Saturday, November 22, 2014

319: Sensible or Not? error

Error Statements: Sensible or Not?
Defend your answer! Here's your claim ... what's your warrant?
  1. There are 138,232 species of butterflies and moths on the Earth. 
  2. The measurement taken by an electronic timer must be more accurate than that taken by stopwatch. 
  3. The relative error that a microbiologist makes in measuring a cell must be less than the relative error that an astronomer makes in measuring the width of a galaxy, because cells are smaller than galaxies. 
  4. The bank teller claims that his errors are random even though they are always to his advantage. 
  5. The 6 billionth person on Earth was born on October 12th 1999, in Bosnia 
  6. I would rather be shortchanged by $1 than by 1% 

ch2.2

Friday, November 21, 2014

Thursday, November 20, 2014

317: Church


How many different math concepts can you use this church as an example for?

Wednesday, November 19, 2014

Tuesday, November 18, 2014

315: Pizza Maker


Talk about the rate at which pizza sauce is being pumped out through the tube ...

Monday, November 17, 2014

314: Stats Starter 2

Following on from yesterday's question, we have a puzzle from the same source.

Which of those central tendency statistics are necessary in order to find the missing numbers? (Necessary meaning that you can't find a particular number without it.) In order words, do we really need all five statistics?


Source.