A basalitc magma with a 87Sr/86Sr ratio of 0.7025 and a Sr concentration of 300 ppm, a sigma18 O value of 0 passes through a granitic crust with a 87Sr/86Sr ratio of 0.750 and a Sr concentration of 150 ppm and a sigma 18 O of +20. Assuming the oxygen content is analogous in the basalt and granite. The basalt assimilates granite in the proportions of 1%, 2%, and 5% What are the O ans Sr isotopic compositions of the contaminated magmas?