Marlene brought a can of polyurethane varnish that was stored at 40°F into her shop, where the
temperature was 74°F. After 2 hours, the temperature of the varnish was 58°F. If the varnish must be
68°F for best results, then how much longer must Marlene wait until she uses the varnish?

Please show explanation:(

Respuesta :

Answer:

1 hour and 6 minutes

Step-by-step explanation:

  • A temperature difference of 58-40 = 18°F was obtained in 2 hours
  • A temperature difference of 68-40 = 28°F will be obtained in x hours

The next proportion must be satisfied:

18 °F / 28 °F = 2 hours / x hours

x = 2*28/18

x = 3.1 hours in total

Given that she has already waited 2 hours, she must wait 3.1 - 2 = 1.1 extra hours. 1 hour is equivalent to 60 minutes, then 0.1 hours is equivalent to 0.1*60 = 6 minutes.