A certain class is divided into two sections A and B of equal number of students. If the ratio of girls to boys for the whole class is 3/5 and the ratio of girls to boys in section A is 5/7. What is the ratio of girls to boys in section B?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
3 (1 to 2)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Let total number of students be T.
Section A and Section B each have T/2 students.
Given: Ratio of girls to boys in the total class is 3:5
So, total girls Gt = (3/8) × T
Total boys Bt = (5/8) × T
Also given: Ratio of girls to boys in Section A is 5:7
So, in Section A (T/2 students):
Girls Ga = (5/12) × T/2
Boys Ba = (7/12) × T/2
Now:
Gt = Ga + Gb
(3/8)T = (5/12)(T/2) + Gb
Gb = (3/8)T - (5/24)T = T/6
Bt = Ba + Bb
(5/8)T = (7/12)(T/2) + Bb
Bb = (5/8)T - (7/24)T = T/3
Therefore:
Gb / Bb = (T/6) / (T/3) = 1/2
