WAEC Past Questions and Answers - Page 1020

5,096.

If 36, p,\(\frac{9}{4}\) and q are consecutive terms of an exponential sequence (G.P), find the sum of p and q.

A.

9/16

B.

81/16

C.

9

D.

9 \(\frac{9}{16}\)

Correct answer is D

GP : 36, P, \(\frac{q}{4}\), q, ... p + q = ?

Recall, common ratio, r = Tn
Tn-1
= T2
T1
= T3
T2
= T4
T3


 

P
36
= 9
4
÷ p ;       p\(^2\) = 9
4
x 36 ;     p\(^2\) = 81  


 

p = 9         ∴      r = T2
T1
    =   9
36
    =  1
4


 

Also r  = T4
T3
   = q ÷ 9
4



∴ \(\frac{1}{4}\) = q ÷ \(\frac{9}{4}\) ;

\(\frac{9}{4}\) = 4q

16q = 9 ,   q = 9
16
   ∴  p + q  =  9 + 9
16
 =  9 9
16

5,097.

Evaluate \(∫^0_{-1}\) (x + 1)(x - 2) dx

A.

7/6

B.

5/6

C.

-5/6

D.

-7/6

Correct answer is D

\(∫^0_{-1}\) (x + 1)(x - 2) dx

= \(∫^0_{-1}\) \(x^2 - x - 2\) dx

Integrated \(x^2 - x - 2\) = \(\frac{x^3}{3} - \frac{x^2}{2} -2\)

5,098.

Which of the following is the semi-interquartile range of a distribution?

A.

Mode - Median

B.

Highest score - Lowest score

C.

1/2 (Upper Quartile - Median)

D.

1/2 (Upper Quartile - Lower Quartile)

Correct answer is D

"Semi" means "half"
Interquartile range = Upper quartile - Lower quartile

Semi interquartile range = 1
2
( upper quartile - lower quartile )

5,099.

A straight line makes intercepts of -3 and 2 on the x and y axes respectively. Find the equation of the line.

A.

2x + 3y + 6 = 0

B.

3x - 2y - 6 = 0

C.

-3x 2y - 6 = 0

D.

-2x + 3y - 6 = 0

Correct answer is D

Recall:

  x
a
+ y
b
=1  



Where 'a' and 'b' are the x and y intercept respectively.
 

  x
-3
+ y
2
=1  



2x-3y = -6
2x - 3y + 6 = 0 -------(1)
multiply through by -1
-2x + 3y - 6 = 0

5,100.

Express \(\frac{4π}{2}\) radians in degrees.

A.

288º

B.

200º

C.

144º

D.

120º

Correct answer is C

\(\frac{4π}{2}\) = \(\frac{4}{5} * 180\)

= 144º