Each boy contributed money equal to the number of girls and each girl contributed money equal to the number of boys in a class of 60 students. If the total contribution thus collected is Tk. 1,600, how many boys are there in the class?

Each boy contributed money equal to the number of girls and each girl contributed money equal to the number of boys in a class of 60 students. If the total contribution thus collected is Tk. 1,600, how many boys are there in the class? Correct Answer 30

Hints: ছেলেদের সংখ্যা x এবং মেয়েদের সংখ্যা y হলে x + y = 60................ (1) এবং, xy + xy = 2xy = 1600 xy = 800 তাহলে, x - y = √(x + y)2 - 4xy = √(60)2 - 4 × 800 x - y = 20............. (2) (1) and (2) no equation 2x = 60 + 20 2x = 80 x = 40
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