The ratio of the mass of sand to cement in a particular type of concrete is 4.8 : 2. If 6 kg of sand are used, how much cement is needed?

3.5 kg

3 kg

2.5 kg

None of these

Given ratio:

Sand : Cement = 4.8 : 2

Let's find the factor by which 4.8 is multiplied to get 6 kg of sand:

6 kg / 4.8 = 1.25

Now, multiply the cement ratio by this factor:

Cement needed = 2 × 1.25

= 2.5 kg