If 12 men and 13 boys can earn $3,720 in 3 days, while 5 men and 6 boys can earn $2,700 dollars in 5 days, how long will it take for 3 men and 4 boys to earn $2,380?

Bonus Question: Can you solve this without working out how much does a man or a boy earn per day?

We have 12M+13B=3720/3 and 5M+6B=2700/5. Let's try to find P and Q so P times the first equation plus Q times the second equations gives something like 3M+4B=X, and then the answer will be 2380/X.

To find P and Q we solve 12P+5Q=3 and 13P+6Q=4, which gives P=-2/7 and Q=9/7, so X=2380/7, and the answer is 7 DAYS.

Posted by Old Original Oskar! on 2006-09-14 15:30:26