a. The distance between B and a is SKM. From a to B, the time of car a is ah, and the time of car B is BH. The two cars start from ABL at the same time and run in opposite directions How long does it take to meet

a. The distance between B and a is SKM. From a to B, the time of car a is ah, and the time of car B is BH. The two cars start from ABL at the same time and run in opposite directions How long does it take to meet

How long does it take to meet each other? Then how far is ab from each other? So the speed ratio of a and B is 4:5, so a 101 ^ (1 / A + 1 / b) = ab/

A and B start at the same time from two places apart from SKM by bicycle. If they are going in the same direction, a will catch up with B when passing M1; if they are going in opposite directions, they will meet each other when passing m2
Let a's velocity be V1 (km / h) and B's velocity be V2 (km / h), then V1 / V2 =?

V1xM1=V2xM1+S
(v1+v2)xM2=S
So s = v1xm2 + v2xm2 = v1xm1-v2xm1
So V2 (M2 + M1) = V1 (m1-m2)
v1/v2=(m2+m1)/(m1-m2)

A. The distance between B and B is SKM. Party A and B go from a and B to meet each other. The journey of Party A is s,
The relationship among s, s a, S B is ()

S = s a + S B

It is known that it takes ah for a to go from place a to place B, and BH for B to go from place B to place A. if a and B set out from both places at the same time and face each other, then they should go from place a to place B
When necessary () H
A.a+b B.(a+b)/2 C.1/a+1/b D.ab/a+b
How does the formula of 1 △ 1 / A + 1 / b = AB / A + B come from,

It takes ah for a to walk from a to B, then the speed of a is: 1 △ a = 1 / A
It takes b h for B to go from B to a, then B's speed is: 1 / b = 1 / b
The sum of their speed is: 1 / A + 1 / b = (a + b) / ab
Meeting time: 1 △ a + B / AB = AB / (a + b)
So D is right