Verbal Reasoning - Mental Ability Questions

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?
642 x 6 ÷ 25 + 4 = ?

In the following question, from the given alternative words, select the word which cannot be formed using the letters of the given word.
RECIPROCATE

If 4Δ2 = 60, 7Δ9 = 160 and 8Δ3 = 110, then find the value of 3Δ2 = ?

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.

3, 5/3, 1/3, ? , -7/3, -11/3

A plane flies 100 km West, then it turns South and flies 150 km, then it turns West and flies 300 km, then it turns to its right and flies 150 km. Where is it now with reference to its starting position?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

RST, XYZ, DEF, ?

P and Q start cycling from the same point. P cycles 18 km North, then turns to her right and cycles 3 km. Q cycles 9 km East, then turns North and cycles 10 km North, then turns left and cycles 6 km. Where is Q now with respect to the position of P?

From the given alternative words, select the word which cannot be formed using the letters of the given word:

PHOTOSYNTHETIC