I was a high school kid, working as a summer intern at the Corcoran Gallery of Art (this was back in my “I want to be a museum curator” phase). In the sales office one Friday afternoon, I overheard a conversation between my two bosses:
Boss 1: “The new ticket collector didn’t keep track of child and adult ticket sales separately this week. All she sent us is the total number of tickets and total revenue. 953 tickets, $9,050 revenue. But the accountant wants us to record child and adult sales separately.”
Boss 2: “Sigh. All right, I guess we’ll have to go get the pile of ticket stubs and sort them all. What a pain in the ass…”
Me (gasps, runs over): “Wait! We don’t need to sort ticket stubs! We already have all the information we need to solve this!”
Boss 1: “We do? How?”
Me: “We need to set up a system of equations! Okay, let’s call A the number of adult tickets and C the number of child tickets. How much does each one cost?”
Boss 1: “Adult tickets are $10, child tickets are $6.”
Me: “Okay! So we know that the total number of tickets is 953 so we can write A + C = 953. And we know the total revenue is $9050 so we can write $10A + $6C = $9050. So we have two equations, two variables:
A + C = 953
10A + 6C = 9050
And now we just solve:
10 (953 – C) + 6C = 9050
4C = 480
C = 120. Therefore A = 953 – 120 = 833.
So that’s the answer — we sold 120 child tickets, and 833 adult tickets.”
My bosses were delighted with the “cool trick” I had used. And I like to think my 7th-grade math teacher would have been tickled pink if she’d seen that go down. How often do you get to actually apply your word-problem skills in real life?
Nothing quite that math-textbook perfect has happened since. Though I keep hoping that someday I’ll overhear someone saying, “My friend and I wanted to meet up for lunch tomorrow, so we agreed to each leave our apartments at noon and walk towards each other’s place until we met. He walks at a rate of 4 mph and I walk at a rate of 3 mph. If only there was some way to figure out where and when we would meet so that I could make a lunch reservation…”