Which function represents the sequence that represents the pattern? Group of answer choices

an = an-1 + 3

an = an-1 - 3

an = 3an-1 - 3

an = 3an-1 + 3

Paint colour a - 15% is black  paint colour b - 60% is blackan x volume of b + 40 ml of atotal volume of the mixture = 40 + xvolume of black in 40 ml = 40*0.15volume of black in x ml = x*0.6the volume of black in mixture = 0.25(40 + x)the total of black in both a and b = (0.15(40) + 0.6x)equate the 2 equations above  (0.15(40) + 0.6x) =  0.25(40 + x)1st response is correct