18 of Susan's muffins weigh the same as 15 of Tom's muffins. How many of Susan's muffins weigh the same as 7 of Tom's muffins?

1 answer

S = weight of Susan's muffin

T = weight of Tom's muffin

18 of Susan's muffins weigh the same as 15 of Tom's muffins means:

18 S = 15 T

3 ∙ 6 S = 3 ∙ 5 T

Divide both sides b 3

6 S = 5 T

Divide both sides by 5

6 S / 5 = T

T = 6 S / 5

T = 1.2 S

1 Tom's muffin weigh the same as 1.2 Susan's muffins.

7 Tom's muffins weigh:

7 T = 7 ∙ 1.2 S

7 T = 8.4 S

8.4 S = 7 T

8.4 Susan's muffins weigh the same as 7 of Tom's muffins.