JAMB Mathematics Past Questions & Answers - Page 179

891.

The diameter of a metal rod is measured as 23.40 cm to four significant figures. What is the maximum error in the measurement?

0.05cm

0.5cm

0.045cm

0.005cm

0.004cm

View answer & explanation

Correct answer is D

Maximum error in measurement to 2 decimal places

Maximum error = \(\frac{1}{2}\) x 0.001

= 0.005

892.

The International Congress of Mathematicians was held in Nice, France in 1970 with 800 people participating. There were 300 from Europe, 200 from America, 150 from Asia, 45 from Africa and 105 from Australia. Representing the above on a pie chart, the angle of the sector representing the participants from Asia is?

150^o

67\(\frac{1}{2}\)^o

67^o

135^o

68^o

View answer & explanation

Correct answer is B

Representing from Asia is 150

\(\frac{150}{800}\) x 360

= \(\frac{135}{2}\)

= 67\(\frac{1}{2}\)°

893.

If \(\frac{3e + f}{3f - e}\) = \(\frac{2}{5}\), find the value of \(\frac{e + 3f}{f - 3e}\)

\(\frac{5}{2}\)

\(\frac{26}{7}\)

\(\frac{1}{3}\)

View answer & explanation

Correct answer is C

\(\frac{3e + f}{3f - e}\) = \(\frac{2}{5}\)

= 3e + f

= 2 x 1

\(\frac{-e + 3f}{3e - f}\) = \(\frac{5 \times 3}{2}\)

= \(\frac{3e + 9f = 15}{10f = 17}\)

f = \(\frac{17}{10}\)

Sub. for equ. (1)

3e + \(\frac{17}{10}\) = 2

3e = 2 - \(\frac{17}{10}\)

\(\frac{3}{10}\)

e = \(\frac{3}{10}\) x \(\frac{1}{3}\)

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

= e + 3f = \(\frac{1}{10}\) + \(\frac{3 \times}{10}\) = \(\frac{52}{10}\)

f - 3e = \(\frac{17}{10}\) - 3 x \(\frac{1}{10}\)

= \(\frac{14}{10}\)

= \(\frac{52}{10}\) x \(\frac{10}{14}\)

= \(\frac{26}{7}\)