Mathematics for IGCSE & O level - Ratio And Proportion (Section 5 - No. 22)
A mixture of concrete is made using cement, sand and water in the ratio 3:2:1. How many liters of sand are needed to make 120 litres of concrete?
20 litres
40 litres
60 litres
80 litres
คำอธิบาย
Total ratio parts is 3+2+1=6. Sand proportion = 2/6 = 1/3. Sand needed = 1/3 * 120 = 40 litres.