Buckets of cement needed is 5 and sand needed is 20
Solution:
Given that Concrete tiles are made using buckets of cement, sand and gravel mixed in the ratio 1 : 4 : 6
cement : sand : gravel = 1 : 4 : 6
Let the cement needed be "1x"
Let the sand needed be "4x"
Let the gravel needed be "6x"
Given that 20 buckets of sand used
4x = 20
x = 5
Thus buckets of cement needed = 1x = 1(5) = 5
Buckets of sand needed = 4x = 4(5) = 20
5 buckets of cement and 20 buckets of sand are needed