Question

Beatrice built about 1/3 of a sandcastle. Linda built 4/7 of the same castle. What fraction of the sandcastle did they build together?

Answer 1

Answer    

Find out the what fraction of the sandcastle did they build together .

To prove

Let us assume that the fraction of the sandcastle  they build together be x .

As given

$Beatrice\ built\ about\ \frac{1}{3}\ of\ a\ sandcastle.$

$Linda\ built\ \frac{4}{7}\ of\ the\ same\ castle.$

Than the equation becomes

$x = \frac{1}{3} +\frac{4}{7}$

L.C .M of (3,7) = 21

solving

$x = \frac{7 + 3\times4}{21}$

$x = \frac{19}{21}$

Therefore the fraction of the sandcastle did they build together be

$x = \frac{19}{21}$

Hence proved