The painter needs at least two gallons of paint to cover the wall.
To get this answer, you first need to find the area of the wall; by multiplying 20.5 x 16.4. This will get you 336.2.
Then, you need to divide 336.2 by 200. This will get you approx. 1.6.
If it's asking for partial gallons as well, stop here. Your answer is 1.6.
If not, continue.
Unless you're including partial gallons, you can't get 1.6 gallons of paint, so you need to round up. This will be 2 gallons.
Check the picture below.
make sure your calculator is in Degree mode.
If you would like to know what is the unit price for the hair shampoo, you can calculate this using the following steps:
500 ml ... $2.10
100 ml ...$x = ?
500 * x = 2.10 * 100 /500
x = 2.10 * 100 / 500
x = $0.42
The unit price for the hair shampoo is $0.42.
