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1.父子二人都是工人,从家到工厂父行全程要40分钟,子行全程要30分钟。如果父先离家5分钟,儿子再出发要走几分钟才能追上父?逻辑思维方法:本题属行程追及问题,追及距离是父先走5分钟所行路程。5÷40=1/8,速度差是1/30-1/40=1/120。所以追及所需时间列式是5÷40÷(1/30-1/40)=1/8÷1/120=15(分钟)。直觉思维方法:因为父先行5分钟,则比子晚到5分钟,追及时应是子行途中的中点。所以列式30÷2=15(分钟)。 2.某工厂生产一批零件,原计划每天生产400个,18天完成。现工作效率提高了20％,实际需要几天完成?逻辑思维方法:先求计划零件总数,再求实际每
1. Both father and son are workers, from home to the factory father and his entire journey to 40 minutes, the whole trip to the bank 30 minutes. If the father first left home for 5 minutes, the son would like to go a few minutes to catch up with his father? Logical thinking method: This issue is a journey to catch up with the problem. 5 ÷ 40 = 1/8, the speed difference is 1 / 30-1 / 40 = 1/120. So chasing the required time formula is 5 ÷ 40 ÷ (1 / 30-1 / 40) = 1/8 ÷ 1/120 = 15 (minutes). Intuitive thinking method: Because the father first line of 5 minutes, than 5 minutes later than the child, chasing the time should be the middle of the child's journey. So the formula 30 ÷ 2 = 15 (minutes). 2. A factory producing a number of parts, the original plan to produce 400 daily, 18 days to complete. Now work efficiency increased by 20%, the actual need a few days to complete? Logical thinking method: first seek the total number of planned parts, and then seek the actual