Answer:
1356cm3
Step-by-step explanation:
when the stone is dropped in to the water the new height is 17.4cm(14+3.4)
find the volume when the height is 14cm and when the height is 17.4cm
24*14*17.4=4716
24*14*14=3360
then subtract the two volumes
4716-3360=1356cm3
Answer: 0.1 or 
Step-by-step explanation:

= 
(One steel rod’s volume) = 3.14 x 4^2 x 20
= 1004.8cm^3
(Used steel) / (One steel rod’s volume) =
(Made steel rod’s number)
The answer is 28