Step-by-step explanation:
let the num be 3x & 4x
3x+4x=28
7x=28
x=28/7
x=4
now, num of girls=3x=3×4=12
& num of boys=4x=4×4=16
Answer:

Step-by-step explanation:
I had a good explanation but the equations overlapped and broke everything. Just google how to divide scientific notation, or use https://www.assignmentpoint.com/science/mathematic/dividing-scientific-notation-numbers.html
Answer:

Step-by-step explanation:

hope this helps you.