6. Solving a chemistry problem

38(3). A weighing of 1.00 g of 1,2-dibromopropane was mixed with 9.00 g of 1,3-dibromopropane and m g of the mixture was again mixed with (10-m) g of 1,3-dibromopropane (both compounds are heavy oils). The latter mixture was photometered at 7.29 µm, where only 1,2-dibromopropane absorbs, and the following data were obtained:
m,g 1.00 2.00 3.00 4.00 5.00
And at λ=7.29 µm 0.040 0.090 0.130 0.170 0.220
the studied mixtures were photometered under similar conditions and obtained Ax 1) 0.19 2) 0.15 3) 0.08
Calculate the mass fraction of 1,2-dibromopropane in the analyzed samples of 1,3-dibromopropane.