The problem asks us to determine the amount of sand, gravel, and cement needed to make 1400 kg of dry concrete, given that the ratio of sand to gravel to cement is 1:2:4.

1. Problem Description

The problem asks us to determine the amount of sand, gravel, and cement needed to make 1400 kg of dry concrete, given that the ratio of sand to gravel to cement is 1:2:

4.

2. Solution Steps

First, we need to find the total ratio:

$Total Ratio = 1 + 2 + 4 = 7$

Now, we need to find out what one ratio represents in kilograms:

$1 Ratio = \frac{1400 kg}{7} = 200 kg$

Now we calculate the amount of each ingredient needed:

Sand: $1 \times 200 kg = 200 kg$

Gravel: $2 \times 200 kg = 400 kg$

Cement: $4 \times 200 kg = 800 kg$

3. Final Answer

Sand: 200 kg

Gravel: 400 kg

Cement: 800 kg