Answer: 5.6kg
Explanation:
Since Jemima filled one fourth of a barrel with compost on Saturday, then the remaining space will be:
= 1 - ¼ = ¾
Since the remaining ¾ space is filled with 4200g of compost, then the compost in the barrel will be
¾ × x = 4200g
0.75 × x = 4200g
0.75x = 4200g
x = 4200g/0.75
x = 5600g
Since 1000g = 1kg
5600g = 5600/1000 = 5.6kg
There is 5.6kg of compost in the barrel.