Last night, I took my kids out for an American children’s holiday known as Halloween.
Kids (and some ahem… adults) dress up in costume (I was a penguin this year), go door-to-door, saying “Trick or Treat” and get free candy from the neighbors.
My three kids brought back a record 420 pieces of candy. 
In today’s New York Times, I learned that in the weeks leading up to this holiday, Americans purchased $2.7 BILLION dollars in candy.
So here’s my challenge for you.
Assuming all of that candy is consumed by someone in America, estimate the total number of calories represented by $2.7 billion in candy.
Assuming 3,500 calories consumed results in a person gaining 1 lb (0.45 kg) in weight, estimate how many pounds (or kilograms) of weight the American population will gain. Add a comment below to post your entry.
The winner will receive public acknowledgement of their estimation skills, and I will send them a portion of the candy “tax” I collected from my kids.
Yes, we tax our kids for a portion of their candy collection, as mom and dad provide “infrastructure” and “chaperone” services.
It’s a useful lesson in taxation.
(We tax at a 33% tax rate.)
Mostly it is an excuse to reduce the amount of sugar they will otherwise end up consuming.
For my kids, it’s an excuse to get rid of the candy they don’t like anyways.
Good luck and Happy Halloween!
Entries will be accepted for next 72 hours, and only entries posted as comments below will be considered. A winner will be announced next week.
UPDATE as of Friday, November 4TH AT 12PM ET: New entries are welcome, but not eligible to win, as contest has closed.
329 thoughts on “A Sweet Estimation Question”
Hi Victor,
Assuming all of that candy is consumed by someone in America, estimate the total number of calories represented by $2.7 billion in candy.
I will add two additional assumptions: 1. All the candy given out during Halloween were bought in fun packs, which reduces the assumed price for a single piece of candy. 2. All the candy will be represented by Butterfingers, which have 85 calories per bar.
Now to the solution: A fun pack of Butterfingers costs $3 and has 18 bars. 1 bag therefore contains 18 x 85 = roughly 1,500 calories a bag. At the 500cal/dollar rate,
The total number of calories purchased in candy is 1.35 trillion calories.
Assuming 3,500 calories consumed results in a person gaining 1 lb (0.45 kg) in weight, estimate how many pounds (or kilograms) of weight the American population will gain.
1.35 trillion calories divided by 3,500 is roughly 390M pounds.
1.25B Pounds
197 million lbs gained by all people.
We know that Americans purchased 2.7 Billion Dollars worth of candy.
Let us assume each candy pack/bar costs $1. Hence, we can say that total candy bars bought is $2.7B divided by $1, which equals 2.7 Billion Candy Packs/Bars.
Now, we can estimate that each candy pack/bar contains 200 calories.
Hence, 2.7 Billion candy packs/Bars will have 2.7 Billion * 200 calories = 540 Billion Calories.
Assuming 3,500 calories consumed results in a person gaining 0.45 kg in weight, then we can say that the total weight (in Kg) gained by the US population is (540 Billion Cal * 0.45 Kg)/3500 Cal which equals 70 Million Kilogrammes.
Therefore, we can say that the American population will gain a total of 70 Million Kg. If we divide this by the total population of the US (320 Million), we get an average weight addition of 70 Million Kg/320 million, which equals 0.22 KG per person.
1 Dollars Spent $2,700,000,000.00
2 Mars variety bag (33.9 oz) cost $10.00
3 Calories in the 33.9 OZ bag 1538
4 Calories per dollar (3/2) 153.80
5 Total calories (4*1) 415,260,000,000.00
6 Calories in 1 LB 3500
7 LB to be gained (5/6) 118,645,714.29
Answer = ~119 million LBs to be gained ( for exact answer see step 7 above)
Thanks to your sweet kids which gave us a very good picture about the collected candies and possible varieties; relying on your kids’ hard job, I make my assumptions base on the embedded picture:
Q1)
-Average candy price per piece: $ 0.50
– Average calories per candy: 100
–> Total calories: $2.7B/0.5 * 100= 540 B calories
Q2)
– I assume only half of collected candies have been consumed (3 tax deduction in all US families plus storage under the kids’ bed or in the pockets)
–> Calories gained from consumed candies :540B/2=270 B
-Total gained weight: 270B/3500= 77 M pounds
Thank you!
49.000.000 pounds.
Bottom line: Pounds Gained: 385,714,285.71
Supporting math:
Dollars: 2,700,000,000
Price per bag: $15
Pieces per bag: 100
Calories per piece: 75
Bags: 180,000,000
Pieces: 18,000,000,000
Calories: 1,350,000,000,000
Calories per pound: 3500
Pounds Gained: 385,714,285.71
Results first:
(i) Total weight gain in the population = 128.57 million lb
(ii) Average weight gain per person (who eats Halloween candy) = 2.64 lb each person
1 candy: average $0.20 and 50 calories
$2.7B in candy: 50 x $2.7B/$0.20 =450B calories
extra weight = 450B calories x 1 lb / 3,500 calories = 128.57 million lb
US Population: 325M
Who eats Halloween candy: Every kid from 4-14 (325M/8=40.625M) Parents “tax” rule (40.625M x 2 parents = 81.25M)
Average weight gain: 128.56 million x (2/3 / 40.625M 1/3 / 81.25M) = 2.64 lb each
Basis:
(a) Avg Candy package cost: $10.00
(b) Avg Calories per package: 9600 (120 pieces x 80 calories per candy)
(c) Total spend: $2.7Bn
(d) Packages: (c) / (a) = 270 million packages
(e) Calories from $2.7Bn spend: (d)x(b) =2,592,000,000,000 calories
(f) % of total calories that cannot be burned and will contribute to weight gain: 60%
(g) Calories that will contribute to weight gain: (e)x(f)= 1.555 trillion calories.
(h) 3500 calories to 1 LB
Total weight gain: 1.555 trillion calories / 3500 = 444,343,000 lbs
US population estimate: 325 million
Avg per capita (Unadjusted): 444,343,000 lbs/325,000,000 = 1.36 lb per capita
Assuming 33% do not eat Halloween candy (health, taste, age, not celebrating Halloween, all/any other reasons etc), candy consuming population is 217,750,000 (3325 million x 67%)
Adjusted weight gain per capita (Adjusted): 444,343,000 lbs / 217,750,000 = 2.04 lbs per capita