About Soroban Expertise I have a systematic and orderly way to organize the facts in a word problem, which (usually) leads clearly to the necessary equation. I think I can help with all types of word problems.
Experience 38 years of teaching college-level math, mostly at a two-year college.
Education/Credentials BS and MS in mathematics, SUNY Albany
Expert: Soroban Date: 2/22/2008 Subject: word problem help
Question Cost of Paint. The first coat of paint for the outside of a building requires 1L of paint for each 10 m2. The second coat requires 1L for every 15 m2. If the cost of paint costs $4.75 per liter, what will be the cost of two coats of paint for the four outside walls of a building 20 m long, 12 m wide, and 6 m height.
Answer Hello, Sherrie!
We just have to "walk" through this problem.
There are two walls that are 20 m long and 6 m high.
They each have an area of: 20 x 6 = 120 mē.
The two walls have an area of: 240 mē.
There are two walls that are 12 m wide and 6 m high.
They each have an area of: 12 x 6 = 72 mē.
The two walls have an area of: 144 mē.
So the four walls have a total area of: 240 + 144 = 384 mē.
The first coat:
One liter of paint covers 10 mē.
To cover 384 mē, it will take: 384/10 = 38.4 liters of paint.
The second coat:
One liter covers 15 mē.
To cover 384 mē, it will take: 384/15 = 25.6 liters of paint.
So, we need: 38.4 + 25.6 = 64 liters of paint.
At $4.75 per liter, the cost is: 64 x $4.75 = $304
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