My dad just yelled to me: "Hey, Robyn, I got a bookkeeping question for you.
"Two people, both aged 60, start saving money monthly, except the second one doesn't start saving until they are both 65. If the first person is saving $700 a month, and the second $100 a month, how long will it be after the second person starts saving for their accounts to be even (excluding interest, simple or otherwise)?"
I looked at my dad, then got up and asked him for a pen and paper. I clarified the problem, considered a tiny bit more and scribbled this down: 4200+700x=1000x then I looked at what I had written and corrected it to: 42000+700x=1000x and handed it to my dad while asking if that was what he had come up with. He said nothing, but asked me if I was sure. I talked through it with him and he was shocked to find out that x=140, or 11 years 8 months, when the two people are almost 77.
I then walked back here while yelling to my stepmom that: "He tricked me, telling me it was a bookkeeping question when it was an algebra word problem!"