JAMB Mathematics Past Questions & Answers - Page 75

371.

An arc of a circle of radius 14cm subtends angle 300° at the centre. Find the perimeter of the sector formed by the arc (take π = \(\frac{22}{7}\))

A.

14.67cm

B.

73.33 cm

C.

101.33cm

D.

513.33cm

Correct answer is C

Length of the arc = \(\frac{\theta}{360} \times 2\pi r\)

= \(\frac{300}{360} \times 2 \times \frac{22}{7} \times 14\)

= \(\frac{220}{3}\)

= 73.33 cm

Perimeter of the sector = Length of the arc + 2r

= 73.33 + 2(14)

= 101.33 cm

372.

The probabilities that John and James pass an examination are \(\frac {3}{4}\)and \(\frac {3}{5}\) respectively. Find the probability of both boys failing the examination.

A.

\(\frac {1}{10}\)

B.

\(\frac {2}{10}\)

C.

\(\frac {9}{20}\)

D.

\(\frac {11}{20}\)

Correct answer is D

Pr(both John and James passed)

  = \(\frac {3}{4}\) x \(\frac {3}{5}\)

  = \(\frac {9}{20}\)

  Pr(john and james failed)= 1- Pr(john and james passed)

  = 1 – \(\frac {9}{20}\)

  = \(\frac {11}{20}\)

  Answer is D

373.

Convert 0.04945 to two significant figures

A.

0.040

B.

0.049

C.

0.050

D.

0.49

Correct answer is B

No explanation has been provided for this answer.

374.

Calculate the total surface area of a cupboard which measures 12cm by 10cm by 8cm

A.

1920cm\(^2\)

B.

592cm\(^2\)

C.

296cm\(^2\)

D.

148cm\(^2\)

Correct answer is B

Total surface area of a cupboard is given by the equation A = 2(lb + bh + lh) L = 12, b = 10, h = 8

  A = 2((12 x 10) + (10 x 8) + (12 x 8))

  A = 2(120 + 80 + 96)

  A = 2 x 296

  A = 592cm\(^2\)

  Answer is B

375.

 

If \(\frac{x}{a + 1}\) + \(\frac{y}{b}\) = 1. Make y the subject of the relation.

A.

\(\frac{b(a + 1 - x)}{a + 1}\)

B.

\(\frac{a + 1}{b(a - x + 1)}\)

C.

\(\frac{a(b - x + 1)}{b + 1}\)

D.

\(\frac{b}{a(b - x + 1)}\)

Correct answer is A

No explanation has been provided for this answer.