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Two numbers are in the tatio 2:3. When 4 is added to each number the ratio changes to 5:7. The sum of the two original numbers is 【两数之比为2：3，当每个数加上4时，新的两数之比为5：7，求原来两数之和】 假设原数为x y x/y=2/3 >> 3x=2y >> x=2y/3 (x+4)/(y+4)=5/7 >>7x+28=5y+20 >>14y/3+28=15y/3+20 y/3=8 y=24 x=16 所以原来两数和为24+16=40 希望回答对你有帮助

hard math