Question

A construction company is working in an area where sand is available free of cost. To make concrete the ratio of cement to gravel is 2:3 and the ratio of gravel to sand is 2: 5. Find the quantity of gravel and cement required if 1000 m3 concrete is needed.​

Answer 1

Given:

Ratio of cement: gravel = 2:3

ratio of gravel:sand = 2:5

To find:

We have to find the quantity of gravel and cement required

Solution:

So let us first find the ratio of cement:gravel:sand

Ratio of cement: gravel = 2:3

Amount of cement = 2/5

Amount of gravel = 3/5

But gravel:sand = 2:5

so sand = 5/7× 3/5   and    gravel= 2/7 × 3/5

Now, ratios are $\frac{2}{5}:\frac{6}{35} :\frac{3}{7}$

Quantity of Gravel =  $\frac{6}{35} (1000)$

                               = 171.42 m³

Quantity of cement = $\frac{2}{5} (1000)$

                                = 400 m³

∴Quantity of Gravel = 171.42m³

  Quantity of Cement = 400m³