2022 - JAMB Mathematics Past Questions and Answers - page 3

21

If a poultry farmer realized 200 eggs from his birds and sold 5 \(\frac{1}{2}\) crates of eggs, what percentages of eggs are left?

A

82.5%

B

15%

C

17.5%

D

85%

correct option: c

5 crates = 30 eggs * 5

= 150eggs

1/2 crate = 15 eggs

total sold = 165

remainder = 200 - 165 = 35 => 17.5% of the realized eggs

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22

Given sec\(^2\)θ + tan\(^2\)θ = 3, find the angle θ

A

90º

B

30º

C

45º

D

60º

correct option: c

sec\(^2\)θ + tan\(^2\)θ = 3

sec\(^2\)θ = 1  + tan\(^2\)θ

: Hence,

1 + tan\(^2\)θ + tan\(^2\)θ = 3

2tan\(^2\)θ = 3 - 1

2tan\(^2\)θ = 2

divide through by 2

tan\(^2\)θ = 1

tanθ =  √1

tanθ = 1

θ = tan\(^{-1}\) (1)

θ = 45º

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23

Find the limit of y = \(\frac{x^3 + 6x - 7}{x-1}\) as x tends to 1

A

9

B

8

C

0

D

7

correct option: a

\(\frac{x^3 + 6x - 7}{x-1}\):

When numerator is differentiated => 3x\(^2\) + 6  

When the denominator is differentiated => 1

Hence,

\(\frac{3x^2 + 6}{1}\)

Substitute x for 1

 \(\frac{3 * 1^2 + 6}{1}\) =  \(\frac{3 + 6}{1}\) 

=  \(\frac{9}{1}\)

= 9

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24

Find the equation of a straight line parallel to the line 2x - y = 5 and having intercept of 5

A

2x + y = 5

B

2x + y = -5

C

2x - y = -5

D

2x - y = 5

correct option: c

If two lines are parallel then their slopes (gradients) will be equal.

Line 2x - y = 5

Equation of a straight line: y = mx + c

y = 2x - 5 

line 2x - y = 5 has a gradient of 2

A parallel line with a gradient of 2 and intercept of 5

=> 2x - y = -5

=> y = 2x + 5

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25

Calculate the median of 14, 17, 10, 13, 18 and 10.

A

12.5

B

13.5

C

13.2

D

14.5

correct option: b

14, 17, 10, 13, 18 and 10.

=> 10, 10, 13, 14, 17, 18

median = \(\frac{13+14}{2}\)

= \(\frac{27}{2}\) or 13.5

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26

Find the equivalence of (10110.011)\(_2\) in base 10

A

26.325

B

24.372

C

42.443

D

22.375

correct option: d

Apply the expansion method on (10110.011)\(_2\)

(1 * 2\(^4\)) + (0 * 2\(^3\)) + (1 * 2\(^2\)) + (1 * 2\(^1\)) (0 * 2\(^0\)) + (0 * 2\(^{-1}\)) + (1 * 2\(^{-2}\))  + (1 * 2\(^{-3}\))

(1*16) + 0 (1*4) + (1*2) + 0 + 0 + (1*\(\frac{1}{4}\)) + (1*\(\frac{1}{8}\)) 

16 + 4 + 2 + (0.25 + 0.125)

22 + 0.375

(10110.011)\(_2\) = 22.375\(_{10}\)

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27

Given that the cost C of running a school is directly proportional to the number of students N, if 20 students cost ₦‎10,000, How many students can ₦‎1,000,000 cover?

A

3000

B

1000

C

2000

D

4000

correct option: c

if 20 students = 10000

₦‎500 per student

₦‎1,000,000 ÷ 500

= 2,000 students

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28

The coordinates of the midpoint of the line joining the points (-3,5) and (2,10) is given by?

A

( \(\frac{1}{2}\), \(\frac{15}{2}\) )

B

( \(\frac{1}{2}\), \(\frac{-15}{2}\) )

C

( \(\frac{-1}{2}\), \(\frac{-15}{2}\) )

D

( \(\frac{-1}{2}\), \(\frac{15}{2}\) )

correct option: d

Given that x\(_1\) = -3,  x\(_2\) = 2,  y\(_1\) = 5,  y\(_2\) = 10

Coordinates of the midpoint of the line = (\(\frac{x_1 + x_2}{2}\) , \(\frac{y_1 + y_2}{2}\))

(\(\frac{-3 +2}{2}\) , \(\frac{5 + 10}{2}\))

=  \(\frac{-1}{2}\)) , \(\frac{15}{2}\))

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29

Evaluate \(^{n^2 + 1}\)C\(_{n+5}\) if n = 3 

A

55

B

45

C

35

D

25

correct option: b

\(^{3^2 + 1}\)C\(_{3+5}\)

\(^{9 + 1}\)C\(_{3+5}\) 

\(^{10}\)C\(_{8}\) = \(\frac{10!}{8! 2!}\)

\(\frac{10 * 9 * 8!}{8! 2!}\) = \(\frac{10 * 9}{2}\)

= 45

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30

Given that S = \(3t^{2}\) + 5t - 10 is the displacement of a particle in metres, calculate its initial velocity.

A

10m/s

B

2m/s

C

5m/s

D

6m/s

correct option: c

s = ut + 1/2at^2

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