Question

[Soái ca tốt bụng]

At a party 60% of the boys are dancing with 80% of the girls. How many people are dancing if there are 35 people? (A pair cludes only one boy and one girl)
Answer:
.......... people are dancing.

Answer 1

[Manix]

If a pair only cludes 1 boy and 1 girl and 60 % of the boys are dancing with 80 % of the girls so 60 % of the boys = 80 % of the girls 

The ratio of the boys and girls is : 60 % : 80 % = \(\frac{3}{4}\)

The number of people is 35 

The number of the boys is : 35 : ( 3 + 4 )  x  4 = 20 ( boys )

The number of the boys are dancing is : 20 x 60 % = 12 ( boys )

The number of people who are dancing is : 12 x 2 = 24 ( 'Cause a pair cludes 1 boy and 1 girl ) ( People )

Ans : 24 people