Then 3a=4b

a=4b/3>b

So a is greater than B.

Of course, I didn't learn negative numbers in the fifth grade, so it is greater than. When I was in junior high school, the negative number may be greater than or less than.

2.b；

2/5×3/4=3/ 10

A: Three tenths.

Obviously, there are 16 girls.

Solution: Girl X was framed.

( 16+x):(36+x)=9: 19

9(36+x)= 19( 16+x)

324+9x=304+ 19x

19x-9x=324-304

10x=20

x=2

A: Then two girls came.

4.4/5×( 1-4/5)=4/25 (m)

A: There are still four-fifths meters left.