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”
Estimate is 236M pounds that the total population will gain.
$2.7B candy
Average cost of candy: $0.50 per ounce (quick estimate from Amazon)
$2.7B is about 5.4B ounces
Assume candy is equal mix of fruity (eg Skittles) and chocolatey (eg Snickers)
Fruity candy: ~400kcal* per 100g
Chocolate candy: ~500kcal per 100g
Average: 450kcal per 100g
Calories per ounce
One ounce is ~28g
100g is about three ounces
450kcal in 100g is ~450kcal in three ounces
One ounce is ~150kcal
5.4B ounces of candy
150kcal per ounce
(5.4B x 1 = 5.4B; 5.4B x 2 = 10.8B; halfway = 8.1B; adjust for 100 = 810B)
810B kcal total
How many pounds?
3500kcal per pound
810B kcal / 3500 = total pounds
(810B kcal/3500 is the same as 810M kcal/3.5)
(810/3 = 270; 810/4 = 202.5; difference from 200 to 270 about 70; half of this is ~35, add a bit to adjust, so say 36; halfway is about 236; fix to millions)
236M POUNDS IN TOTAL
*assuming that calories in this question is the food calorie, technically kcal
1. 675billion calories in that amount of candy
2. 190m pounds of weight gained
Hi Victor,
I have estimated that Americans will gain approximately 217,555,787 pounds from Halloween candy sales.
Regards,
Vasili Kharchenko
AVERAGE CANDY PRICE:
Prices for candy bags (top sellers during this week) may vary between $10 (high-end brands) and $5 (popular), taxes included, for a typical 40 oz bag in large stores (like Walmart etc), thus between c$25 and c$12.5 per oz. Smaller shops sell smaller bags at higher prices, maybe around c$25-30/oz. Halloween featured candies may sell even higher such as 30-35c$/oz. Fancy candies may drive the sales during this period so we can set an average price just below 30c$/oz or around 1c$/g to keep calculations easy.
AVERAGE CALORIES PER CANDY:
Candies are mainly made of sugar which has around 4 cal/g. However they contain also fat which is more intensive in calories, 9 cal/g. Assuming candies are made 80% of sugar and 20% from fatty sources, their weighted calories turn out to be about 5 cal/g.
TOTAL CALORIES SOLD:
Assuming sales are $2.7B, then:
WEIGHT_CANDIES_SOLD = $2.7B/(1c$/g) =2.7*10^11 g = 270,000 ton
TOT_CALORIES_SOLD = 5 cal/g*0.27Gg = 1.35*10^12 cal = 1350 billion calories
TOTAL WEIGHT GAINED:
Given that 3,500 cal correspond to 1 lb or 0.45 Kg, then:
TOTAL_WEIGHT_GAINED = 1.35*10^12 cal/3,500 cal = 386 million Kg.
If we monetize this weight:
WEIGHT_PER_$ = 0.14Kg/$ (each dollar “buys” 0.14 Kg, that is 3$ buy about 1 lb)
Another interesting metric can be the equivalent cost of calories:
CAL_PER_$ = (5 cal/g)/ (1c$/g) = 500 cal/$ (each dollar buys 500 cal)
CONCLUSION:
The US population gains about 386 million Kg or 858 million lb (about 1.2 Kg per person). However, given that most of the candies are not equally eaten among the population, we can expect kids between 6 and 15 years (about 40 millions, considering an equally distributed population of 320 million people over a life expectancy of 80 years) to gain more weight. Specifically, assuming kids (between 6 and 15) eat 50% more than the rest of the people, it means that:
40M*1.5x 280M*x = 386 M Kg, giving x = 1.14 Kg.
Therefore kids can gain an average of 2x=1.7 Kg from celebrating Halloween week.
77.1 million pounds of weight, if a piece of candy is assumed to have 50 calories, shared by the American population who collected Halloween candy.
Hi Victor,
This is my estimation:
As long as your problem involves 2 questions, I have divided it in 2 parts.
First part is divided in two calculations:
– 2.7 blns / average price of a oz of candy = # oz in 2,7 blns of candies. The value at the denominator has to be estimated. To do so I considered an average on Snickers and M&Ms prices per oz on Wallmart website. My estimated value is around 0.3071$.
Hence: 2,700,000,000/0.3071 = 8,793,103,448 oz
[Please note that I prefer not to round so much values as the task here is to get a precise answer, otherwise I could have rounded 0.3071 with 3*10^(-1), so the calculation would have been far much easier, but less precise: 27*10^(8) / 3*10(-1) = 9*10(9), 9 blns. In the following steps I will go for the precise values rather than approximations]
– 8,793,103,448 oz * average calories in 1 candy oz = calories in 2.7 blns of candy. Second multiplier has to be estimated. I have converted the value found on this link: https://www.caloriecount.com/calories-candies-caramels-i19074; I have found: 110.56 calories/oz. The result is: 972,192,080,520.38 total calories.
[here again I could have done 9*10^(9) / 1*10^(2) = 9*10^(11), rounding down 110.56 as before I had rounded up the first result, by dividing for a smaller number].
Second part involves the following calculation:
– calories in 2,7 blns candy / 3,500 = lb gained by US population. Result is: 277,769,165.9 lb.
– value in lb *0,45 = value in kgs
Result is 277,769,165.9*0,45 = 124,996,124.6 kgs increase in US population.
I hope you will like my answer. Happy Halloween!
Assume 1 candy cost $5
Total revenue realized $2.7 billion.
Total number of candies brought:- (2.7*100*100000)/5= 54 *100000
Assuming 1 candy has 100 calories
Total number of calories in all candies:- 5400*100000
3500 calories–> .45 kg
5400000000–> (.45*5400000000)/ 3500
Approx 700000 kg
Assumptions:
Average Trick or Treater Haul: 100 Pieces (your kids were on record pace)
Number of People Trick or Treater Age (include Adult kids): 1/6 Americans or 50M Trick or Treaters (ToTs)
Calories per Piece: 75
Findings:
Number of Trick or Treat Pieces: 5B Pieces (100 Pieces X 50M ToTs)
Gut Check $2.7B Sales / 5B pieces = ~ $.50 / Piece
Collective Pounds Gained = 107M Pounds ((5B pieces * 75 Calories per Piece)/3500 Calories per Pound)
Pound per Trick or Treater = ~ 2 Pounds (107M Pounds / 50M ToTs)
Gut Check 2 Pounds after consuming 100 pieces of candy – definitely 🙂
Here’s how I would do it if in an interview setting i.e. no access to any further data or a calculator.
Additional assumption: $1 of candy provides 500 calories.
Hence, $7 of candy provides 3500 calories which results in a gain 1lb.
$2.7 billion would therefore result in a weight gain of roughly 385 million lbs for the entire American population.
24.3 million kgs of weight gainrd at the entire population level assuming 35 cal per candy and 50 cents per candy.