Valentine's Math Quiz: All The Math You Will Do For Love

Dating and love - what do they have to do with math? This Valentine's quiz created by TheMathMom for the Boston Globe demonstrates the applicability of math to love and dating affairs. Ready for the challenge?

Puzzle #1:  Cake and Ex Math
You were planning to make a little Valentine's Day cake for you and your boyfriend, but he's just told you that his ex-girlfriend and her three roommates are joining you for dessert. (Don't worry, they're just friends.)

Do you:
a. Double the recipe

b. Triple the recipe

c. Quadruple the recipe

d. Dump the entire bowl of batter over his head.

Correct answer:

I would count B or D as the correct answers J

Puzzle#2: The Math of Your Heels
You are picking up an outfit for the tonight’s date.  Got the dress, and the purse.  What heel should you go for?  If your date is 6’0” (in his shoes) and your height is 5’7”, how high should your heel be for you to stand shoulder-to-shoulder with your date? 

Pick one: 3”, 4”, 5”.





Correct answer:
5" because there are 12" in one foot and 6'0" - 5'7" = 12" - 7" = 5"


Puzzle #3:  Celebrity Ring
Did you hear the latest gossip about the famous model-singer couple? He was about to propose to her on the Valentine’s Day but she told him she wants a square ring. Jeweler told him it will be more expensive.  Do you think the jeweler is taking advantage of him?

Answer option 1: Sure he does. Who wouldn't with all the money this guy has? Just tell him to bend the round ring into a square with pliers.

Answer option 2: I don’t think so. Perhaps square ring will require more material, in order to fit on the same finger.  Square should contain the original ring’s circle inside.  

Correct answer: 2. If original ring has diameter D and perimeter Pi x D=3.14 x D, square perimeter will be 4 x D. He sure needs to pay more for a square ring.

Puzzle #4: Peaceful Dinner
Your husband is taking you out on Valentine’s Day, but because his sister and her husband are in town from NY, he has also invited them, as well as his parents, to join you at the restaurant.  You can deal with this as long as you don’t have to sit next to your mother or sister in-law, who would probe you relentlessly with the procreation questions.  And your husband is still so upset with the Patriots’ loss to the Jets that it is better to avoid letting him sit right next to the New Yorkers.  Your parents-in-law love to share the main course and should sit next to each other.  What would be the best sitting arrangement for a round table? (Note: it could be good to draw each of the answers.)

Answer options:

1. You, your husband, his mom, his sister, sister’s husband, your father-in-law.
2. You, your husband, his mom, his dad, his sister, sister’s husband.
3. Your husband, you, father-in-law, mother-in-law, sister-in-law, sister’s husband

Correct Answer: B is correct. A separates between your mother and father-in-laws, but remember - they want to share the course. C places your husband right next to his outspoken Jet’s fan sister.


Puzzle #5: Mirror Math

You are prepping yourself to a Valentines night in front of a mirror, winking to your reflection and singing into a hair brush: Tonight’s gonna be a good night!  Your spouse opens the door and sneaks in to tell you to hurry. Suddenly you see in your spouse’s reflection on the mirror this black crawling creature on his right pocket. The kids left the tarantula’s cage open again! Do you scream:

1. Careful, your right pocket!
2. Careful, your left pocket!
3. Smash the tarantula on your husband with the hairbrush risking killing both. pliers.

Correct answer is B: mirrors do a horizontal reflection, so what appear on the right pocket of your reflection is on the left pocket of the real you.

Puzzle #6: Valentine's Chocolates

You want to bring a box of Valentine’s chocolates to the office for your boss and three coworkers. There are 12 candies in the box -- three fudge, three almond clusters, three caramels, and three coconut -- and you would like each person to get three. One box is enough, right? But then you remember: Mildred is allergic to nuts, Jack has dentures and can't eat chewy foods, your boss would like all the fudge, and nobody will touch the coconut. How many boxes do you need to buy to avoid any unpleasantness? 

1. 1 box
2. 2 boxes
3. 3 or more boxes

Correct answer is 3. If everyone is going to get three (and your boss gets all the fudge ones), then one box definitely won't cut it. After figuring in everyone's issues in box two, and keeping in mind you'd like some, you must go to three boxes for everyone to get three or more candies.

Puzzle #7: Math and Diamonds

All those commercials convinced you that nothing says “I love you” better than diamonds. You decide to venture into the Kingdom of Diamonds outlet and splurge on one for your girlfriend. The store advertised a 30% off sale for Valentine’s. You see that there is a ring that is ½ off. You figure, given the additional 30% discount you would get the ring for only 20% of the original price.  True or false?

Correct answer: False. Assume that ring is $100. ½ off is $50.  30% off from $50 means that you pay 100%-30%=70% of the $50 price.  It is: $50 x 0.7 = $35.  This is 35% of the original price, or 100%-35%=65% discount..


Puzzle #8: TV Math
Now, in the post-Super bowl and pre-Oscar screen relaxation, you decided to make a special present for your loved one for Valentine’s Day and buy a new flat screen 54” TV. Your old TV is also HD but 27”.  In the Valentine card, you want to write how much larger your viewing area will be now. Is it larger by 2, 4 or 8?








Correct answer is 4 as TV size is measured by diagonal.  Therefore a 27" diagonal TV is 1/4 size of the 54" diagonal TV as pictured here.

Puzzle #9: Vow Renewal

Your wedding anniversary was on January of 2011. This Valentine’s atmosphere put you in a romantic mood and you decided to plan a trip to Hawaii and renew your vows for your next year’s Silver Anniversary.  You call a travel agent and want to schedule the ceremony exactly 25 years after your wedding day but you don’t have the calendar with you. What day of the week would your wedding anniversary be in on January 2012 if this year it was on Friday?  

Pick an answer:  

1. Friday
2. Saturday 
3. Sunday.

Correct answer is Saturday. 365/7 has a remainder of 1, as a result every date shifts 1 day forward each year, except in leap years when it shifts by 2 days forward. Therefore, your Silver anniversary falls on Saturday next year.




Puzzle #10: Cheating

Your husband is telling you that he is going to spend Valentine’s eve with his only brother's wife's only brother-in-law's wife. What shall you do to him?

1. kill
2. leave
3. kiss

Correct answer is kiss because your husband’s only brother's wife's only brother-in-law's wife is you.

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Would you like a power-point version of this quiz to share with your students, teachers or your kids? Download it here.

Read the Math Mom's column The Math of Dating -- Mark Yourself Excelled for more about the math as the guiding hand in some of your romantic adventures.