WAEC Mathematics Past Questions & Answers - Page 294

1,466.

Calculate the total surface area of a cone of height 12cm and base radius 5cm. [Take π = 22/7]

A.

180 5/7cm2

B.

240 2/7cm2

C.

235 5/7cm2

D.

282 6/7cm2

E.

361 3/7cm2

Correct answer is D

No explanation has been provided for this answer.

1,467.
1,468.

Solve the simultaneous equations y = 3x; 4y - 5x =14

A.

-2,-6

B.

2,6

C.

2,-6

D.

-2,6

E.

-1,-3

Correct answer is B

y = 3x  ... (i);

4y - 5x =14  ... (ii)

Put 3x for y in (ii).

4(3x) - 5x = 14

12x - 5x = 14

7x = 14 ⟹⟹ x = 2.

y = 3x = 3(2) = 6

(x, y) = (2, 6)

1,469.

Factorize 2x\(^2\) - 21x + 45

A.

(2x - 9)(x - 5)

B.

(2x-15)(x + 3)

C.

(2x +15)(x - 3)

D.

(2x -15(x - 3)

E.

(2x - 9)(x + 5)

Correct answer is D

2x\(^2\) - 21x + 45

= 2x\(^2\) - 15x - 6x + 45

= x(2x - 15) - 3(2x - 15)

= (x - 3)(2x - 15)

1,470.

Write as a single fraction: \(\frac{5}{6r} - \frac{3}{4r}\)

A.

r/12

B.

12/r

C.

1/6r

D.

r/6

E.

1/12r

Correct answer is E

\(\frac{5}{6r} - \frac{3}{4r}\)

= \(\frac{10 - 9}{12r}\)

= \(\frac{1}{12r}\)