Todd uses 21 white tiles & some black tiles to make a mosaic. The mosaic has a total area of 144 square centimeters. Each tile has an area of 3 square centimeters. How many black tiles did Todd use?Explain.

Todd used 27 black tiles.

Step-by-step explanation:

Let x represent the number of black tiles that Todd used.

Todd uses 21 white tiles & some black tiles to make a mosaic. This means that the total number of white and black tiles that Todd used is 21 + x

Each tile has an area of 3 square centimeters. This means that the total area covered by the white tiles is

21 × 3 = 63 square centimeters

Also, the total area covered by the black tiles is

3 × x = 3x square centimeters

The mosaic has a total area of 144 square centimeters. This means that

3x + 63 = 144

3x = 144 - 63

3x = 81

x = 81/3 = 27

x = 25

step-by-step explanation:

a^2+b^2=c^2

7^2+24^2=c^2

49+576=625

sqrt625=25

x=25

$450.00 for 6 weeks

or

$300

step-by-step explanation:

$200.00 for first week $50.00 x5 equals $250 plus $200 equals $450.00 for six weeks.

$200 for first week

$200 x 0.10 = $20

$20 x 5 = $100

$200 + $100 = $300