The ratio of boys to girls at a college is 4:5. How many boys and are there if the total num of students is girls 3321?

2 Answers
Jan 10, 2017

Answer:

boy count is 1476

Explanation:

There is an important difference between the way counts are viewed in ratio to that in fractions.

The ratio of boys : girls #-> 4:5# so you have 4 boys and 5 girls making the whole count #4+5 = 9# in its simplest form.

So to change the ratio proportion into fraction proportion we have:

boys #-> 4/9# of the whole.

girls #->5/9# of the whole.

It is given that the whole is 3321 therefore the count of boys is:

#4/9xx3321 = 1476#

Feb 19, 2018

Answer:

An alternative interpretation of the question.
Proves that my other solution is the correct one.

Explanation:

There is a problem with interpreting the question part:
"the total num of students is girls 3321"

It would make more sense if worded:

#color(brown)("Case 1. 'if the total num of students is 3321' ")#

#color(brown)("Case 2. 'if the total num of girls is 3321'")#

My other answer assumes case 1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Answering as if Case 2 is applicable")#

Using ratio in fraction FORMAT.

#color(brown)("Note that this is not fractions of the whole.")#

#("boys")/("girls") -> 4/5-=x/3321#

Multiply both sides by 3321

#x=2656.8#

This #ul("answer does not make sense")#

You can not have part of a boy. So the other solution where I address Case 1 must be the correct interpreatation