JAMB Mathematics Past Questions & Answers - Page 25

Vertically opp angles are equal ∠CDE = 70°

Sum of interior angles in a quadilateral = 360°

(90 + 90 + 70 + t)° = 360°

t° = 360° - 250°

t° = 110°

Mensah’s age is 5. Thus,

Joyce’s age is 15 (5*3=15)

The difference between their ages is 10 (15–5=10)

As we ought to find how many years Joyce’s age will be twice of Mensah’s age, we should write down the following :

15+X=2*(5+X)

15+X=10+2X lets add (-10-X) to both sides of the equation and

15+X-10-X = 10+2X-10-X

5=X —-> X=5

After 5 years Joyce’s age will be 20 (15+5=20)

After 5 years Mensah’s age will be 10 (5+5=10)

After 5 years Joyce will be twice as old as Mensah (10*2=20)

The sum of 2 $\frac{1}{6}$ and 2$\frac{7}{12}$

= $\frac{13}{6}$ + $\frac{31}{12}$

=  $\frac{13 \times 2 + 31}{12}$ 

= $\frac{26 + 31}{12}$

= $\frac{57}{12}$

What should be subtracted from $\frac{57}{12}$ to give 3$\frac{1}{4}$

$\frac{57}{12}$ - y =  3$\frac{1}{4}$

: y = $\frac{57}{12}$ - 3$\frac{1}{4}$ = $\frac{57}{12}$ - $\frac{13}{4}$

y = $\frac{57 - 3 \times 13}{12}$ =  $\frac{57 - 39}{12}$ 

y =  $\frac{18}{12}$

y =  $\frac{3}{2}$ or 1$\frac{1}{2}$ 

6pq-3rs-3ps+6qr = 3 (2pq - rs - ps + 2qr)

= 3 ({2pq + 2qr} {-ps - rs})

= 3 (2q{ p + r} -s{p + r})

= 3 ({2q - s}{p + r})

Simply add odd number starting from '3' to the next number

2

2 + 3 = 5

5 + 5 = 10

10 + 7 = 17

17 + 9 = 26

The fifth term = 26