I came across a problem about proportion as follow:
There are 5 girls for every 12 boys, if the total number of children is 5200, how many are boys and girls?
I tried following solution but the answer result to decimal number. Since this is number of children, so I believe it should be whole numbers. But I could not come up with the answer of whole number. :( Please help.
Girls = 5/17 X 5200 = 1529.41
Boys = 12/17 X 5200 = 3670.59
Thanks in advance.
Your reasoning is correct: if you subdivide the children in groups of $17$ each, $5$ girls and $12$ boys, there should be no remainder. Then you just multiply the number of groups by $5$ to know the number of girls. It's easier to do the subtraction than multiplying by $12$ to know the number of boys, but the result will be obviously the same.
However, $5200$ is not divisible by $17$, so who wrote the problem made a mistake. Maybe they wanted to write $5202$.
Another possibility is that two children got lost: go and look for them!
;-)