A, B two people each walk a section of road, they use the time ratio is 4:5, the speed ratio is 5:3, then they walk the distance ratio is? It's urgent! There is another question. The sum of the two simplest fractions with the same denominator is 9 / 10. Their molecular ratio is 7:11. The two fractions are () and ()

A, B two people each walk a section of road, they use the time ratio is 4:5, the speed ratio is 5:3, then they walk the distance ratio is? It's urgent! There is another question. The sum of the two simplest fractions with the same denominator is 9 / 10. Their molecular ratio is 7:11. The two fractions are () and ()

Do this problem remember: speed times time = distance
Time a: time B
4 ：5
Speed A: speed B
5 ：3
Route a: route B
Five times four: five times three
20：15
4：3
Next:
Make an equation
Let their denominator be X
7 / x + 11 / x = 9 / 10
18 / x = 9 / 10
X = nine tenths divided by 18
X = nine tenths multiplied by one eighteenth [his reciprocal]
X=20
That's good: one is 7 out of 20, and the other is 11 out of 20
I'm right

A and B set out from a to B on the same route from the same place at the same time. It is known that the distance from a to B is s. A completes the first half of the distance at the speed of V1 and the second half at the speed of v2. B completes the whole distance at the speed of V1 in the first half of the time and V2 in the second half of the time (2) judge which of a and B reaches B first

Solution: (1) x = s2v1 + s2v2 = s (V1 + V2) 2v1v2, y = sv1 + V22 = 2sv1 + V2; (2) X-Y = s (V1 + V2) 2v1v2-2sv1 + V2 = s (V1 − V2) 22v1v2 (V1 + V2), when V1 = V2, two people arrive at the same time; otherwise, they arrive first