The sum of the four members of Xiaojun's family is 129 years old, Xiaojun is 7 years old, and his mother is 30 years old. The sum of the ages of Xiaojun and his grandfather is 5 years older than the sum of his parents. What are the ages of his grandfather and his father?

The sum of the four members of Xiaojun's family is 129 years old, Xiaojun is 7 years old, and his mother is 30 years old. The sum of the ages of Xiaojun and his grandfather is 5 years older than the sum of his parents. What are the ages of his grandfather and his father?

129 - (30 + 7) = 92 (years old). Suppose father's age is x years old, then grandfather's age is 92-x years old. The meaning of the question is: 7 + 92-x = x + 30 + 5, & nbsp; 99-x = x + 35, & nbsp; & nbsp; & nbsp; 2x = 99-35, & nbsp; & nbsp; & nbsp; & nbsp; 2x = 64, & nbsp; & nbsp; & nbsp; & nbsp; X = 64 △ 2, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 32, grandfather's age is 92-32 = 60 (years old). Answer: grandfather is 60 years old, father is 32 years old

Xiaojun was 28 years younger than his father last year. His father's age is eight times that of Xiaojun this year

1. Taking Xiaojun's age this year as one, my father is eight times his, that is eight, that is to say, my father is seven times older than Xiaojun, and my father is 28 years older than Xiaojun, which means that seven is 28, one is four, and Xiaojun is one, so Xiaojun is four years old
2. If Xiaojun is x years old, his father is 8x years old. 8x-x = 28, x = 4

Xiao Dong's father is a taxi driver. In order to calculate the fuel consumption per kilometer of the car, he was operating along the north-south direction one morning, which is a detailed record
In view of the driving situation, he stipulated that the south is positive and the north is negative. The following is his driving record this morning: (unit: kilometer)
+1,-16,+4,-5.2,-3.8,+15,-6,-9
It is known that the taxi consumed 9.6 liters of fuel this morning. Do you know the fuel consumption per kilometer of Xiaodong dad's taxi?

Drunk dream string,
6 (1 + 16 + 4 + 5.2 + 3.8 + 15 + 6 + 9) = 0.16 (L)