JAMB Mathematics Past Questions & Answers - Page 73

361.

In a class of 40 students, 32 offer Mathematics, 24 offer Physics and 4 offer neither Mathematics nor Physics. How many offer both Mathematics and Physics?

A.

4

B.

8

C.

16

D.

20

Correct answer is D

Let the number of people that offer both Mathematics and Physics = y

Then, \((32 - y) + y + (24 - y) + 4 = 40\)

\(60 - y = 40 \implies y = 20\)

\(\therefore\) 20 students offer both Mathematics and Physics.

362.

What is the product of 2x2 − x + 1 and 3 − 2x

A.

4x3 − 8x2 + 5x + 3

B.

−4x3 + 8x2 − 5x + 3

C.

−4x3 − 8x2 + 5x + 3

D.

4x3 + 8x2 − 5x + 3

Correct answer is B

(2x2 - x + 1) × (3 - 2x);

3(2x2 - x + 1) - 2x (2x2 - x + 1)

6x2 - 3x + 3 - 4x3 + 2x2 - 2x

-4x3 + 8x2 -5x + 3

363.

Evaluate 1 − (\(\frac{1}{5}\) x 1\(\frac{2}{3}\)) + (5 + 1\(\frac{2}{3}\))

A.

4

B.

3

C.

\(\frac{22}{3}\)

D.

3\(\frac{2}{3}\)

Correct answer is C

1 − (\(\frac{1}{5}\) x 1\(\frac{2}{3}\)) + (5 + 1\(\frac{2}{3}\))

1 − (\(\frac{1}{5}\) x \(\frac{5}{3}\)) + (5 + \(\frac{5}{3}\))

1 − \(\frac{1}{3}\) + \(\frac{20}{3}\)

= \(\frac{22}{3}\)

364.

Find the range of the following set of numbers 0.4, −0.4, 0.3, 0.47, −0.53, 0.2 and −0.2

A.

1.03

B.

0.07

C.

0.03

D.

1.0

Correct answer is D

0.4, −0.4, 0.3, 0.47, −0.53, 0.2, −0.2 Range is the difference between the highest and lowest value i.e Highest − Lowest − 0.53, −0.4, −0.2, 0.2, 0.3, 0.4, 0.47 0.47 is the highest − 0.53 is the lowest ∴ = 0.47 − (− 0.53) ∴0.47 + 0.53 = 1.0

365.

If α and β are the roots of the equation 3x2 + 5x - 2 = 0, find the value of 1/α + 1/β

A.

\(\frac{-5}{3}\)

B.

\(\frac{-2}{3}\)

C.

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

D.

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

Correct answer is D

1/α + 1/β = β+α/αβ
3x2 + 5x - 2 = 0
x2 + 5x/3 - 2/3 = 0
αβ = -2/3
β+α = -5/3
Thus; β+α/αβ = -2/3 -2/3 = -5/2