Club Math is the first-ever student math club at Kaua‘i Community College. The club is interested in the practicality and usefulness of mathematics in everyday living. The primary goal is to involve the community by promoting this ideal. What follows
Club Math is the first-ever student math club at Kaua‘i Community College. The club is interested in the practicality and usefulness of mathematics in everyday living. The primary goal is to involve the community by promoting this ideal. What follows is last week’s math puzzle followed by the answer.
The club will submit weekly brainteasers for the education page. The following week, the answer will be provided.
How old is Grandpa?
“My grandson is about as many days as my son is weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 160 years. Can you tell me my age in years?
Solution:
This problem is conveniently solved by writing down the necessary equations. Note that there are 12 months in a year, 52 weeks in a year, and 365 days in a year.
Let m = my age in years. If ‘s’ is my son’s age in years, then my son is 52s weeks old. If ‘g’ is my grandson’s age in years, then my grandson is 365g days old. Thus:
365g = 52s (This can be approximated to 7g = s)
Since my grandson is 12g months old, 12g = m
Since my grandson, my son and I together are 160 years, g + s + m = 160
The above system of three equations in three unknowns (g, s and m) can be solved as follows:
g + 7g + 12g = 160
20g = 160
g = 8
Since 12g = m
12 X (8) = m
96 = m
So, grandpa is 96 years old.
This week’s brain teaser
Numbers can talk:
If 125207 is “Hi” and 031993121212 is “Dude” then 125207031993121212 is “Hi Dude.”
What is 799717777010909230151693122001983?
