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JAMB Mathematics Past Questions & Answers - Page 161

801.

Find the missing numerator 5x+1 - 31x - 7x1x21 = ?x+1.

A.

-1

B.

x - 1

C.

3(15x)x+1

D.

1

E.

3(1 - 5x)

Correct answer is D

5x+131x7x1x21=?x+1

5(x1)3((x+1))7x1x21

= 5x5+3x+37x1x21

= x1x21

= x1(x1)(x+1)

= 1x+1.

The numerator = 1.

802.

Simplify 102 + log105

A.

500

B.

2 log10 5

C.

10

D.

25

E.

log105 x 10100

Correct answer is E

102 + log105 = log10 10100 + log105

= log105 x 10100

803.

Given log 2 = 0.69, log3 = 1, 10 and log7 = 1.90, all to a fixed base, find log 10.5 to the same base without using tables.

A.

1.03

B.

2.31

C.

3.69

D.

10.5

E.

25

Correct answer is B

log 10.5 = log 212

= log 21 - log 2

= log(3 x 7) - log 2

= log 3 + log 7 - log 2

= 1.10 + 1.90 - 0.69

= 3 - 0.69

= 2.31

804.

Solve the equation for the positive values of θ less than 360o. 3 tan θ + 2 = -1

A.

135o or 315o

B.

45o or 135o

C.

315o or 180o

D.

315v + 45o

E.

360o or 315o

Correct answer is A

3 tan θ + 2 = -1

3 tan θ 33 = -1

θ = tan -1(-1)

θ = 360o - 45o

= 315o

θ = 180 - 45o = 135o

805.

Find the area of the curved surface of a cone whose base radius is 6cm and whose height is 8cm. (take π = 227)

A.

188.57cm2

B.

1320cm2

C.

188cm2

D.

188.08cm2

E.

10cm2

Correct answer is A

S = curved surface area = πrL

= 227 x 6 x 10

= 188.57cm2