"State the value of 170.6041 (a) correct to three significant figures, (b) correct to five significant figures." The correct answers are (a) 171 and (b) 170.60. This is because expressing a quantity in significant figures requires that the permitted number of figures express the value closest to the actual quantity. Thus 171 is closer to 170.6041 than is 170 because 170.6 is beyond the half-way mark between 170 and 171. 170.60 is closer to 170.6041 than 170.61 would be because 170.604 is less than half way between 170.60 and 170.61
The O-Level question (3) is so badly presented as to be meaningless. As another correspondent has already stated, let us see it in its original form. If that is the original form then the question should be declared void. There are many ways of interpreting what is written. I attempted to decipher it two ways, giving answers of x=2.2 and x=10. I have not exhausted all the possibilities.