**Answer:**

9

**Step-by-step explanation:**

**Answer:**

otal concrete weight =2400kg

have 15% water means in 2400kg of concrete 360kg is water.ramaining 2040kg is of cement,sand and stone.in the ratio of 1:2:5 respectively.then according to ratio.weight of cement=255kg

weight of sand=510kg

weight of stone=1275kg

**Step-by-step explanation:**

**Answer: The answer is B**

**Step-by-step explanation:**