Quantitative Aptitude - Arithmetic Ability Questions

In the following question, select the odd letter pair from the given alternatives.

Select the odd number from the given alternatives.

If a = 3+23-2, b = 3-23+2 then a2+b2-ab ?

The 3rd and 9th term of an arithmetic progression are -8 and 10 respectively. What is the 16th term?

If 4x - 5y = -37 and 7x + y = -16, then x - y = ______

The mean score in a test of the 12 boys in a class was 16 while the overall mean of the 30 students in the class was 18.1. What was the mean score of the girls?

ΔXYZ is similar to ΔPQR. If ratio of Perimeter of ΔXYZ and Perimeter of ΔPQR is 4:9 and if PQ = 27 cm, then what is the length of XY (in cm)?

P and Q can do a project in 20 and 12 days respectively. In how many days can they complete 40% of the project if they work together?