Respuesta :

Answer:

12 hours

Step-by-step explanation:

Step 1:

70 : 1             Ratio

Step 2:

70 : 1 = 840 : x       Equation

Step 3:

840 = 70x      Multiply

Step 4:

x = 840 ÷ 70      Divide

Answer:

12 hours

Hope This Helps :)