1No.: A section of road is divided into three sections: uphill, flat and downhill. The ratio of the length of each section is 1:2:3, and the ratio of the time when someone walks in each section is 4:5:3. It is known that his uphill speed is 3 kilometers per hour and the distance is 50 kilometers. How long did it take him to walk the whole distance? (The problem of the sixth grade last semester)
Answer: 50×11+2+3 (one sixth) = 50×1/6 = 25/3km25/3 ÷ 3 = 25/9 hours, 25/9 ÷ 4/4+6.
Question 2: Subtract A from the numerator of the fraction of 29/43, add A to the denominator, and the fraction becomes 3/5, so as to find the natural number A.
Answer: 29+43=72 72÷(3+5)=9 29-27=2 This natural number is 2.
Equation:
20× 10%=(20+x)×22%
Solution: 2+0.3x = 404+0.22x.
0.3x=4.4+0.22x-2
0.3 = 2.4+0.22 times
0.2x-0.22x=2.4
x=30
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