- Mariana debe tomar dos pastillas; una cada 6 horas y otra cada 9 horas. Si a cierta hora toma las dos pastillas juntas, ¿después de cuantas horas volverá a tomarlas simultáneamente?

Mariana takes the two pills together after 18 hours.

Step-by-step explanation:

Mariana must take two pills; one every 6 hours and another every 9 hours.

She take two pills together. Let she takes the two pills together after t hours at the time when she take initially.

To find the time to take the two pills together, take the least common multiple of 6 and 9.

6 = 2 x 3

9 = 3 x 3

So, the least common multiple is 2 x 3 x 3 = 18

So, she takes the two pills together after 18 hours.

2.83941151 would be the answer you're looking for! : )