I am pretty sure the answer is 15 boys at the beginning of the assembly.
That would mean that there were 28 girls there, and if 40% of them left, which would mean that 8 left, leaving 20 girls. This would leave the assembly with a 3:4 ratio of boys to girls.
In this problem, this is the case with Angle 1 and Angle 2, hence their relation is that they are vertical, and option C is correct
The solution is:
.1*50+x=.25(50+x) 5+x= 12.5+ .25x
x-.25x=12.5-5 .75x=7.5 x=7.5 or .75
Answer:

Step-by-step explanation:
Divide n by 100,000.
This gives us the "number of times 100,000 fits in n", or, "how many 100,000's n is", or as the hint says, "how many times larger n is than 100,000".
All represented by this formula:
