JAMB Mathematics Past Questions & Answers - Page 115

571.

The bar chart shows different colours of cars passing a particular point of a certain street in two minutes. What fraction of the cars is yellow

A.

\(\frac{1}{5}\)

B.

\(\frac{2}{25}\)

C.

\(\frac{4}{15}\)

D.

\(\frac{3}{25}\)

Correct answer is D

\(\begin{array}{c|c} \text{colour of cars} & \text{Number (frequency)} \\ \hline yellow & 3 \\white & 4\\ red & 8\\ green & 2\\ blue & 6\\ black & 2\\ \hline & 25 \\ \hline\end{array}\)

Thus, the fraction of the total numbers that are yellow is \(\frac{3}{25}\)

572.

Find the value of \(\theta\) in the diagram

A.

60o

B.

100o

C.

120o

D.

30o

Correct answer is C

Using cosine formula (t\(\sqrt{3}\))2 = t2 + t2 - 2t2 cos\(\theta\)

3t2 = 2t2 - 2t2 cos\(\theta\) = 2t2(1 - cos\(\theta\))

1 - cos\(\theta\) = \(\frac{3t^2}{2t^2}\) = \(\frac{3}{2}\)

cos = 1 - \(\frac{3}{2} = -\frac{1}{2}\)

\(\theta\) = cos-1(-\(\frac{1}{2}\)) = 120o and 240o

N.B 0 \(\geq\) \(\theta\) 360

573.

In the figure PQR a straight line segment, PQ = QT. Triangle PQT is an isosceles triangle, < SRQ is 75o and < QPT IS 25o. Calculate the value of < RST

A.

50o

B.

25o

C.

55o

D.

45o

Correct answer is C

< T = \(\frac{x}{1}\) = 25o (PQ = QT)

< SQR = 2(25o) = 50o (sum of interior angle)

< Q + < R + < S = 180o

50o + 75o + < S = 180o = 125o + < S = 180o

< S = 180o - 125o = 55o

574.

Triangle SPT is the solution of the linear inequalities

A.

2y - x - 2 \(\leq\) 0, y + 2x + 2 \(\geq\) 0, x \(\geq\) 0

B.

2y - x - 2 \(\geq\) 0, y + 2x + 2 \(\leq\) 0, -2 \(\geq\) x \(\geq\) -1

C.

-2 \(\geq\) x \(\geq\) 2, y \(\leq\) 0, y + 2x + 2 \(\geq\) 0, x \(\geq\) 0

D.

2y - x - 2 \(\geq\) 0, y + 2x + 2 \(\geq\) 0, y \(\leq\) 0, x \(\geq\) 0

Correct answer is C

No explanation has been provided for this answer.

575.

The cumulative frequency curve represents the ages of ages of students in a school. What age group do 70% of the students belongs?

A.

17.5 - 20.5

B.

16.5 - 19.5

C.

15.5 - 19.5

D.

15.5 - 18.5

Correct answer is A

No explanation has been provided for this answer.