Respuesta :

4 cups of pecans = 5 cups of walnuts
x cups of pecans = 8 cups of walnuts

CROSS MULTIPLY
4*8 =5x
5x = 32

DIVIDE BOTH SIDES BY 5

5x/5 = 32/5
x=6.4

Therefore, 6.4 cups of pecans would be added to 8 cups of walnuts