The equation is solved by converting two thirds and four sevenths to have the common denominator of 21. The calculation results in a solution of seventeen twenty ones (17/21) for the given fractions.
To Solving Fractions the equation by finding a common multiple, we look at the fractions two thirds (2/3), four sevenths (4/7), and fifteen twenty ones (15/21).
First, we need to find a common denominator for these fractions, which happens to be 21 since it's the least common multiple of 3, 7, and 21.
We can now convert each fraction:
Two thirds (2/3) can be converted to fourteen twenty ones (14/21) because 2 multiplied by 7 equals 14 and 3 multiplied by 7 equals 21.
Four sevenths (4/7) converts to twelve twenty ones (12/21) because 4 multiplied by 3 equals 12 and 7 multiplied by 3 equals 21.
Fifteen twenty ones (15/21) remains as it is because the denominator is already 21.
Now, we can add and subtract these numbers:
14/21 - 12/21 = 2/21
2/21 + 15/21 = 17/21
Therefore, the solution to the given equation is seventeen twenty ones (17/21).