2008 AMC 10B Problems/Problem 18

Revision as of 11:21, 4 January 2009 by Person1133 (talk | contribs)

Problem

Bricklayer Brenda would take nine hours to build a chimney alone, and bricklayer Brandon would take 10 hours to build it alone. When they work together, they talk alot, and their combined output decreases by 10 bricks per hour. Working together, they build the chimney in 5 hours. How many bricks are in the chimney?

A) 500 B) 900 C) 950 D) 1000 E) 1900

Solution

Let x be the number of bricks in the chimney. Using distance = rate * time, we get x = (x/9 + x/10 - 10)(5) solving for x, we get 900 (B)

See also

2008 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 17
Followed by
Problem 19
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 10 Problems and Solutions
Invalid username
Login to AoPS