If the accumulation of a resource is given by ∫13f(t) dt=10\int_{1}^{3} f(t) \, dt = 10∫13f(t)dt=10, what is the result of ∫312f(t) dt\int_{3}^{1} 2f(t) \, dt∫312f(t)dt?
20
-20
5
-5