Elementary school math problem! ! Hurry up ~ ~

1. 10000 Vietnamese dong is equivalent to 6 yuan RMB.

2. The original 16 girls.

3. The speed ratio is 5: 4, and we can meet in 20/9 hours.

1.80 USD is converted into 1 120000 VND, then 1 USD can be converted into 1 120000 VND divided by 80 = 14000 VND.

Then 8.4 RMB can be converted into 14000 VND, and it can be concluded that 1 VND can be converted into 0.0006 RMB, so 10000 VND can get 6 RMB.

2. Suppose there are X boys, then there are 2x/3 girls, (2x/3+4)/x=5/6, and finally x=24, then there are 15 girls.

3. Let the total distance be m, then v 1:v2=(m/4)/(m/5)=5:4.

Assuming that the time they spend is x, then mx/5+mx/4=m, you can get x=20/9.

So tired. I haven't done math problems for a long time. I don't know if I'm right.