Final answer:
To find the total amount of compost in the barrel, we add the amount filled on Saturday to the amount filled on Sunday. There are 16.8 kilograms of compost in the barrel.
Step-by-step explanation:
To find the total amount of compost in the barrel, we need to add the amount Jemma filled on Saturday (one-fourth of the barrel) to the amount she filled on Sunday (4,200 g).
Since one-fourth of a barrel is equal to one-fourth of the total amount of compost, we can use this information to set up a proportion:
1/4 = 4200/x
Cross-multiplying, we get:
x = 4 * 4200 = 16800 g
Since the question asks for the answer in kilograms, we need to convert grams to kilograms by dividing by 1000:
x = 16800 / 1000 = 16.8 kg
Therefore, there are 16.8 kilograms of compost in the barrel.