There is a few ways to get the result.
Lets try this.
First calculate how many minutes are in the 5 hours.
60min*5=300min - in 5 hours
Now, knowing that quarter is 15min we can divide 300 by 15 to get the result, so
300:15=20 - its the result.
Answer:

Step-by-step explanation:
-This is an LCM problem.
-To simplify, we introduce a least common multiplier which is equivalent the product of the denominators:

#We introduce the LCM and adjust the fractions based on it :

Hence, the simplified form of the fraction is: 
Answer: 4.6 horas.
Step-by-step explanation:
Podemos calcular el tiempo necesario por una llave:
si sabemos que se llena en 8 horas con 4 llaves, entonces una sola llave va a tardar 4 veces 8 horas en llenar el tinaco, es decir, una sola llave tarda:
4*8h = 32 horas
ahora, si usamos 7 llaves, el tiempo necesario va a ser un septimo de eso:
(32 h por llave)/(7 llaves) = 32/7 horas = 4.6 horas.
You combine the like terms to get
2s^2y^2-4a^2sy+2a^4