Jamb 2008 Mathematics Questions
Question 21:
A binary operation * is defined on the set of positive integers is such x*y = 2x-3y+2 for all positive integers x and y. The binary operation is
- A Commutative and close on the set of positive integers
- B Neither commutative nor closed on the set of ppositive integers
- C Commutative but not closed on the set of positive integers
- D Not cummutative but closed on the set of positive integers
Question 22:
A binary operation on the real set of numbers excluding -1 is such that for all m, n ∈ R, mΔn = m+n+mn. Find the identity element of the operation.
- A 1
- B Zero
- C -<sup style='font-size: smaller;'>1</sup>/<sub style='font-size: smaller;'>2</sub>
- D -1
Question 23:
In the diagram above, PQ//RS. The size of the angle marked x is
- A 100<sup style='font-size: smaller;'>o</sup>
- B 80<sup style='font-size: smaller;'>o</sup>
- C 50<sup style='font-size: smaller;'>o</sup>
- D 30<sup style='font-size: smaller;'>o</sup>
Question 24:
Find the exterior angle of a 12 sided regular polygon
- A 12<sup style='font-size: smaller;'>o</sup>
- B 24<sup style='font-size: smaller;'>o</sup>
- C 25<sup style='font-size: smaller;'>o</sup>
- D 30<sup style='font-size: smaller;'>o</sup>
Question 25:
In the diagram above ∠ OPQ is
- A 90<sup style='font-size: smaller;'>o</sup>
- B 53<sup style='font-size: smaller;'>o</sup>
- C 36<sup style='font-size: smaller;'>o</sup>
- D 26<sup style='font-size: smaller;'>o</sup>