Verbal Reasoning - Mental Ability Questions

The missing number in the series 9 81 ? 6561 59049

Rajitha has a calculator, which has 10 digits. She want to clean the calculator by removing all the keys and while reassembling it, she interchanged the locations of 3 pairs of keys. For example, if she placed the key ‘3’ in the place of the key ‘7’, she placed the key ‘7’ only in the place of the key ‘3’ and not any other key. All keys that were interchanged corresponded only to numbers. Later, she input some calculations and obtained outputs as provided in the table below. The input is shown in terms of the keys that Kavitapressed, while the output is the output displayed by the calculator.

Output:

1.   95 + 84=128
2.   128 + 64=195
3.   912 + 43=942
4.   178 + 19=192

Question :

Which of the following pair of digits is unchanged ?

If '/' denotes 'subtraction', '-' denotes 'addition', '+' denotes 'multiplication' and 'x' denotes 'division', which of the following is the value of the expression

182/91x7+3-1

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?
_qr_srq_p_rs_r_p

Synonym for the word : Bleak

Priya cycles 5 km North, then turns East and cycles 4 km, then turns South and cycles 5 km, then turns to her right and cycles 6 km. Where is she now with reference to her starting position?

Which of the following diagrams indicates the best relation between Females, Doctors, and Patients?

Nitin correctly remembers that Nidhi's birthday is before Friday but after Tuesday. Dheeraj correctly remembers that Nidhi's birthday is after Wednesday but before Saturday. On which of the following days does Nidhi's birthday definitely fall?