Question

David cuts a cake into two equal halves. He cuts one half into smaller pieces of equal size. Each of these small pieces weighs twenty grams. If he has seven pieces of the cake in total, then how heavy was the original cake?

• A. 120 grams
• B. 180 grams
• C. 300 grams
• D. 240 grams

Answer 1

The correct option is D 240 grams

Let the weight of original piece be $x$ grams.
Then the weight of one half of the cake is $\frac{x}{2}$ grams.

There are a total of seven pieces.
The number of smaller pieces is six which come from the other half.

Weight of each small piece is $(\frac{1}{6}\times \frac{x}{2})$ which is equal to 20 grams.

Therefore,
$\frac{x}{12}=20$
$x=20\times 12$
$x=240$.

Hence, the total weight of the cake is 240 grams.