For the answer to the question above,
4 shovels of sand are used for every 5 shovels of gravel
4s : 5g
How many shovels of gravel are needed for 64 shovels of sand?
64s : Xg
We need to calculate the value of X
4s : 5g
64s : Xg
4s.Xg = 5g.64s
X = (5g*64s)/4sg
= 5*64/4
= 5*16
= 80
80 shovels of gravel are needed.