There are some adults and children at a party. 190 more boys then joined in, while 65 adults left. As a result, the percentage of girls in the party decreased from 36% to 24%. (a) Find the percentage increase in the total number of people at the party. (b) Find the number of girls at the party.

(a)

“The percentage of girls at the party decreased from 36% to 24% implies” :

At first :

(adults + boys) ——-> 64%

In the end :

adults – 65 + boys + 190 = (adults + boys) + 125 ——-> 76%

64u + 125 ——-> 76p

36u ——-> 24p

3u ——-> 2p

64u + 125 ——-> 114u

1u ——-> 2.5

100u ——-> 250

125/250 = 50%

(b)

36 x 2.5 = 90

Ans : (a) 50%; (b) 90 girls.