Un anuncio luminoso tiene focos de cuatro colores diferentes. los focos azules encienden cada 12 segundos, los rojos cada 18 segundos y los verdes cada 30 segundos los focos blancos pertenecen siempre encendidos. ¿cada cuantos minutos encienden todos los mismos focos al mismo tiempo?

Abank manager wants to encourage new customers to open accounts with principals of at least $2,500. he decides to make a poster advertising a simple interest rate of 3%. what must the principal be if the bank manager also wants to advertise that one can earn $10 the first month? can the poster correctly say, "open an account of $2 comma 500 and earn at least $10 interest in 1 month! "?