Question

Your local radio station is having their yearly MP3 and concert ticket giveaway. For one minute, every 5th caller will win an MP2 player and every 7th caller will win concert ticket. You were just the first caller to win both and MP3 player and concert tickets! What number caller where you?

Answer 1

The 13th number caller

Explanation:

It's quite easy, but I used a bit of differential calculus, L'Hospital's Rule, and Taylor Series. Hope I helped!