Correct Answer - Option 4 : 75: 48
Given:
The ratio of sand to gravel in a mixture is 15: 8 while that between gravel and cement is 10: 12
Calculation
Sand: gravel = 15: 8
Gravel: cement = 10: 12
Then,
Sand: gravel: cement
15: 8: 8
10: 10: 12
Then sand: gravel: cement = 150: 80: 96
Sand: Cement = 150: 96 = 75: 48
Hence, the Sand: Cement = 75: 48