Sally and Hassan share a chocolate bar. Sally eats 1/4 of the chocolate bar and Hassan eats 2/5. The bar has a mass of 100 grams. How much is left?

Answer 1

Sally eats 1/4 of the chocolate bar, which is 1/4 * 100 = 25 grams.
Hassan eats 2/5 of the chocolate bar, which is 2/5 * 100 = 40 grams.
Together, they eat 25 + 40 = 65 grams.
Therefore, there is 100 - 65 = 35 grams of chocolate left.