JAMB Mathematics Past Questions & Answers - Page 196

976.

Given a regular hexagon, calculate each interior angle of the hexagon

A.

60o

B.

30o

C.

120o

D.

45o

E.

135o

Correct answer is C

Sum of interior angles of polygon = (2n - 4)rt < s

sum of interior angles of an hexagon

(2 x 6 - 4) x 90o = (12 - 4) x 90o

= 8 x 90o

= 720o

each interior angle will have \(\frac{720^o}{6}\)

= 120o

977.

A construction company is owned by two partners X and Y and it is agreed that their profit will be divided in the ratio 4:5. At the end of the year, Y received N5,000 more than X. What is the total profit of the company for the year?

A.

N20, 000

B.

N25,000

C.

N30,000

D.

N15,000

E.

N45, 000

Correct answer is E

Total sharing ratio is 9 X has 4, Y has 4 + 1 If 1 is N5000 Total profit = 5000 x 9 = N45,000

978.

If M represents the median and D the mode of the measurements 5, 9, 3, 5, 7, 5, 8 then (M, D) is

A.

(6, 5)

B.

(5, 8)

C.

(5, 7)

D.

(5, 5)

E.

(7, 5)

Correct answer is D

first re-arrange the given data in the form 3, 5, 5, 7, 8, 9 Mean(x) = \(\frac{\sum x}{N}\)

= \(\frac{42}{7}\)

= 6, re-arrange thenumbers,

3, 5, 5| 7, 8, 9 median(D) = 5

(m, d) = (5, 5)

979.

Measurements of the diameters, in centimeters, of 20 copper spheres are distributed as shown below
\(\begin{array}{c|c} \text{Class boundary in cm} & \text{frequency} & \\\hline 3.35 - 3.45 & 3\\ 3.45 - 3.55 & 6\\ 3.55 - 3.65 & 7\\ 3.65 - 3.75 & 4\end{array}\)
What is the mean diameter of the copper spheres?

A.

3.40cm

B.

3.58cm

C.

3.56cm

D.

3.62cm

Correct answer is C

\(\begin{array}{c|c} \text{x(mid point)} & f & fx\\ \hline 3.4 & 3 & 10.2 \\ 3.5 & 6 & 21.0\\3.6 & 7 & 25.2\\3.7 & 4 & 14.8\end{array}\)

\(\sum f\) = 20

\(\sum fx\) = 71.2

mean = \(\frac{\sum fx}{\sum f}\)

= \(\frac{71.2}{20}\)

= 3.56

980.

If sin \(\theta\) = \(\frac{x}{y}\) and 0o < 90o then find \(\frac{1}{tan\theta}\)

A.

\(\frac{x}{\sqrt{y^2 - x^2}}\)

B.

\(\frac{y}{x}\)

C.

\(\frac{\sqrt{y^2 + x^2}}{y^2 - x^2}\)

D.

\(\frac{y^2 - x^2}{x}\)

Correct answer is D

\(\frac{1}{tan\theta}\) = \(\frac{cos\theta}{sin\theta}\)

sin\(\theta\) = \(\frac{x}{y}\)

cos\(\theta\) = \(\frac{\sqrt{y^2 - x^2}}{y}\)