Divide 4/5 by 5/8 since that would tell you how many walls he can paint in an hour.
4/5 walls÷5/8 gallons=1.28walls/gallon.
Mammals: If the number of Mammal exhibits is 25 and there are 75 total exhibits, the Mammal exhibits are 1/3 of the total exhibits at this Zoo. The ratio for 1/3 is 1:3, which is 25:75 in most complex form. That's 33.3 as a percentage, or 33.3%.
Reptiles: If the number of Reptile exhibits is 15 and there are 75 total exhibits, the reptile exhibits are 1/5 of the total exhibits here. The ratio for 1/5 is 1:5, which is 15:75 fully written out. This as a percentage is 20%.
I'll message you the other half of the answers.
You want to isolate the variable 'y'.

Subtract 10 to both sides:

Divide -3 to both sides:
Answer:
3 obreros tardaran 225 minutos en completar el trabajo.
Step-by-step explanation:
Sea R la velocidad con la que un obrero puede construir 1 muro.
Sabemos que 15 obreros construyen un muro en 45 minutos, entonces:
(15*R)*45min = 1 muro
Con esta ecuación podemos encontrar el valor R
R = (1 muro)/(15*45min)
Ahora queremos saber cuando tiempo tardan 3 obreros en construir un muro, entonces tenemos que resolver:
(3*R)*T = 1 muro
Reemplazando el valor de R obtenemos:
(3*(1 muro)/(15*45min))*T = 1 muro
T = (1 muro)*(15*45 min)/(3*1 muro)
T = 5*45min = 225 min
3 obreros tardaran 225 minutos en completar el trabajo.