







Manipulating an equation 
20150605 

From Leigh: Hi, I'm having trouble trying to find out how the equation y=mx+b for b comes up with the answer b=ymx. Could you please assist me with this Answered by Penny Nom. 





1/6k=11 
20141113 

From Marty: Using the balance method, what is the answer to 1/6k=11, trying to find what k equals. Thanks Answered by Penny Nom. 





A balance puzzle 
20130114 

From Emily: I'm stuck on this problem and feel that it can't work! The problem is: there is a door with a balance scale on it. In order to open the door, you have to use the 5 weights to balance the scale. On the left side you have 2 boxes to place the weights and on the right side you have 3. You're 5 weights are as follows: 1lbs, 2lbs, 3lbs, 4lbs, 5lbs. How do you place the weights so that the scale is balanced? Answered by Penny Nom. 





Ramon has 6 puppies 
20110417 

From Mary: Ramon has 6 puppies. Five of the 6 weigh the same and one puppy is heavier. If Ramon had a balance scale, what is the least number of times he could weigh the puppies to be sure he could determine which puppy was heavier? Answered by Penny Nom. 





There are 12 balls and one balls weight is different than the others 
20100812 

From david: if there was 12 balls and one balls weight is different than the other and use a balance 3 times is there a possible way to find which weigh different Answered by Robert Dawson. 





12 coins 
20100707 

From Eden: We have 12 coins same in size and shape and also weight.
But among these, one coin which has same size and shape, but not in weight
and we can't know that this coin was lighter or heavier.
We must decide which coin was lighter or heavier among these 12 coins in
4 times of weighting with scale. Answered by Stephen La Rocque and Tyler Wood. 





What is the account value after 3 years? 
20080710 

From Carlos: Question
Suppose that you deposited $3,000 at the beginning of each year for three years in a savings account earning 4%. What is the account value after 3 years (approx)?
a. 9,120
b. 9,211
c. 9,739
d. 9,989 Answered by Penny Nom. 





Balancing on a fulcrum (net torque and equilbrium) 
20080115 

From Eric: If I have a 4" bar that has no weight value with a 275lb. weight on one side
and a 125lb. weight on the other side what would be the folcrum point? Please
keep the answer very simple. Also is there a fixed equation to figure folcrum points?
Is there an equation for if the 4" bar had a weight value? Answered by Stephen La Rocque. 





Apples, oranges, bananas and pears 
20061230 

From Richard: If 6 oranges weights as much as 4 apples, 5 bananas weights as much as 3 pears, and ten bananas weights as much as 8 oranges. How many pears and apples would you need to have their weights balanced. Answered by Penny Nom. 





Twelve golf balls 
20051228 

From Todd: You have 12 golf balls and 11 of them are the exact same weight, but one of them is either a little heavier or a little lighter. You only have three attempts to weigh the balls. How can you determine which ball weighs more/less than the rest? Answered by Penny Nom. 





A counterfeit coin 
20040123 

From Kim: You are considering buying 45 silver coins that look alike, but you have been told that one of the coins is a lightweight counterfeit. Find the least number of weighings on a balance scale that you can use to be certain you have found the counterfeit coin? Answered by Penny Nom. 





Splitting weight 
20030210 

From Jin Ho: A balance scale has only two weights, 1 ounce and 4 ounces. In only three weighings split 180 ounces of seed in two bags of 40 and 140 ounces. Answered by Penny Nom. 





A Weighty Problem 
19990617 

From A parent: When using a balance scale, weights can be placed on either side of the scale. For example, if a 10 pound weight provides a counter balance to an object and a 7 pound weight, then the object must weigh 3 pounds. What four weights can be used to weigh objects of 1, 2, 3 ... 38, 39, 40 pounds? Answered by Penny Nom. 





Levers 
19990113 

From Lane Campbell: 1. Solve for x or y. (a)
<4m><4m><xm >
_____________________________________________________
^ ^ ^ ^
25N 5N ^ 15N
Answered by Jack LeSage. 





A balance problem 
19961118 

From Jack N. Bussell: There are 12 coins which look exactly the same, however one of them is heavier or lighter than the rest. Using a pointer balance scale, can you identify the odd coin and whether it is heavy or light in 3 weighings? Answered by Harley Weston. 





A coin problem 
19960416 

From Julie Hebert and Simon Hamel: How many weighings would you need to find out which pile is fraudulent? Answered by Penny Nom. 

