SOLUTION: Ferdie was having a big party and he was excited. He had been practicing his opening lines all week and as soon as he he got to the part, 20 girls at the party left. There now rema

Algebra.Com
Question 212509: Ferdie was having a big party and he was excited. He had been practicing his opening lines all week and as soon as he he got to the part, 20 girls at the party left. There now remained 2 boys for each girl. A lot of the other boys thought the party was pathetic, so 20 of the boys also left. There were now 3 times as many girls as boys. How many boys and girls were at the party when Ferdie got there?
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Ferdie was having a big party and he was excited. He had been practicing his opening lines all week and as soon as he he got to the part, 20 girls at the party left. There now remained 2 boys for each girl. A lot of the other boys thought the party was pathetic, so 20 of the boys also left. There were now 3 times as many girls as boys. How many boys and girls were at the party when Ferdie got there?
--------------------------
Let original # of girls be "G"; Let original number of boys be "B".
---------------------
After 20 girls left:
B = 2(G-20)
--------------------------
After 20 boys left:
(G-20) = 3(B-20)
-------------------------
Substitute for "B" and solve for "G":
G-20 = 3(2G-40-20)
G-20 = 3(2G-60)
G-20 = 6G-180
5G = 160
G = 32 (original number of girls)
---
B=2(G-20)
B = 2*12 = 24 (original number of boys)
===========================================
Cheers,
Stan H.

RELATED QUESTIONS

Write a linear system as a model of the following situation, then solve. Your school's... (answered by solver91311)
A party of fishermen rented a boat for $240. Two of the men had to withdraw from the... (answered by stanbon)
Ben was in charge of ordering 35 pizzas for the office party. He ordered three types of... (answered by josmiceli)
Blaise rode his bike to his friend Elroy's house, which was 15 miles away. After he had... (answered by ankor@dixie-net.com)
A man came upon a bridge, he knew a train was coming soon, but he thought he could make... (answered by ankor@dixie-net.com)
Blaise rode hi bike to him friend elroy's house, which was 15 miles away. After he had... (answered by ankor@dixie-net.com)
Al-Kwarizmi's will was drawn up when he was near death, and his wife was expecting their... (answered by Theo)
A man lived 1/6 of his life as a child. 1/7 of his life as an adolescent and 1/12 of his... (answered by ankor@dixie-net.com)
A man lived a fourth of his life as a boy, a fifth as a young man and a third as an... (answered by Fombitz,ganesh)