Question

Central portion of a propeller shaft is made of
1. Steel shaft
2. Gun metal Shaft
3. Steel tube
4. Cast iron​

Answer 1

Answer:

Let the total students be x.

Passed students=90%×100=0.9x

Failed students=(100%−90%)x=0.1x

Given,

0.1x=80⟹x=800 

Hence total candidates=800

Answer 2

3 steel tube

is right answer