The elder brother's age is three times that of the younger brother, three times that of the elder brother, and the younger brother's 1 times, with a difference of two times (the difference between elder brother and younger brother will never change). When the younger brother is three times, the older brother is three times +2 times =5 times; When the younger brother's age is the older brother's present age, that is to say, when the younger brother is 5 times, the older brother is 5 times +2 times = 7 times, 5 times +7 times = 12 times (that is, 48 years old), 1 times is 48 divided by 12, which is equal to 4 years old, and the younger brother's present age is 3 times 4 times equal to/.