Does each function describe exponential growth or decay? y=100(1 - 1/2)^t

y=0.1(1.25)^t

y={(1 - 0.03)^1/2}^2t

y=426(0.98)^t

y=2050(1/2)^t

Isabelle is mixing red and blue paint to make purple paint she adds 3/10 of a fluid ounce of red to 12/25 of a fluid ounce of blue to make 1 1/30 fluid ounces of purple how many fluid ounces of red paint ounces of red paint will she need to make 3 fluid ounces of purple paint