2. The sum of the ages of father and son is 63 years old, the age of father is 1/5, and the age of son is 1/2. How old are the father and son? Father+son =63 1/5 father = 1/2 son; Father =5/2 children; Substitute into the above formula: 7/2 sub = 63; child = 18; Father =45
3. Party A completed a project in 6 days, and Party B 10 days. Now Party A has completed13 of the total amount, and Party A and Party B have completed the rest. How many days can it be finished? X = (2/3)/(1/6+110) = 2/3 * 60/16 = 2.5 days.
4. For projects A and B, the number of the two teams should be adjusted due to work needs. Team A exchanges 1/5 of its own number with 1/4 of team B. After the exchange, the numbers of the two teams are equal. It turns out that the simplest integer ratio between Team A and Team B is (5/6) 4/5a+1/4b =1/5a+3/4b; 3/5a = 1/2b; A/B = 1/2*5/3=5/6
It takes 8 hours for the bus to go from A to B, and it takes 12 hours for the train to go from B to A. At present, two trains leave from two places at the same time. How long did the bus walk when they met? 3/5 buses complete the journey in 8 hours, with an hourly rate of 1/8. Similarly, the train completes the journey at112 per hour, and the two trains complete the journey at1/8+112 = 5/24.