WAEC Past Questions and Answers - Page 4242

21,206.

If the second and fourth term of a G.P are 8 and 32 respectively,what is the sum of the first four terms?

A.

28

B.

40

C.

48

D.

60

E.

68

Correct answer is D

ar = 8 .....(1)


ar3 = 32 .....(2)


divide (2) by (1)

r2 = 4 r = 2 ∴ a = 4



S =
a(rn - 1)/r - 1


S =
4(24 - 1)/2 - 1
= 60

21,207.

If 3loga + 5loga - 6loga = log64, what is a?

A.

4

B.

6

C.

8

D.

16

E.

32

Correct answer is C

loga3 + loga5 - loga6

log(
a3 * a5/a6
) = loga64


a2 = 64 a = 8

21,208.

The surnames of 40 children in a class arranged in alphabetical order. 16 of the surnames begins with O and 9 of the surname begins with A, 14, of the letters of the alphabet do not appear as the first letter of a surname


If more than one surname begins with a letter besides A and O, how may surnames begin with that letter

A.

2

B.

3

C.

4

D.

5

E.

6

Correct answer is E

14 of the letters of the alphabet do not appear as the first letter of surname
∴ the no. of letters that appeared = 26-14 = 12 alphabets
15 surnames begin with 10 letters beside O and A
∴ 6 surnames begin with a letter

21,210.

If Q = (all perfect squares less than 30) and P = (all odd numbers from 1 to 10). Find Q ∩ P.

A.

(1, 4, 9, 16, 25)

B.

(1, 3, 4, 5, 7, 9, 16, 25)

C.

(1, 3, 5, 7, 9)

D.

(1, 9)

E.

Φ

Correct answer is D

Q = {1, 4, 9, 16, 25} P = { 1, 3, 5, 7, 9}
Q ∩ P = { 1, 9}