JAMB Mathematics Past Questions & Answers - Page 337

1,681.

If log104 = 0.6021, evaluate log1041/3

A.

0.3011

B.

0.9021

C.

1.8063

D.

0.2007

Correct answer is D

log1041/3 = 1/3 log104

= 1/3 x 0.6021

= 0.2007

1,682.

Simplify \(\frac{3^{-5n}}{9^{1-n}} \times 27^{n + 1}\)

A.

32

B.

33

C.

35

D.

3

Correct answer is D

\(\frac{3^{-5n}}{9^{1-n}} \times 27^{n + 1}\)

\(\frac{3^{-5n}}{3^{2(1-n)}} \times 3^{3(n + 1)}\)

\(3^{-5n} \div 3^{2(1-n)} \times 3^{3(n + 1)}\)


\(3^{-5n - 2(1-n) + 3(n + 1)}\)


\(3^{-5n - 2 + 2n + 3n + 3}\)

\(3^{-5n + 5n + 3 - 2}\)

\(3^{1}\)

= 3

1,683.

Calculate the time taken for N3000 to earn N600 if invested at 8% simple interest

A.

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

B.

3 years

C.

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

D.

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

Correct answer is A

Using \(S.I =\frac{P \times T \times R}{100}\)

\(600 =\frac{3000 \times T \times 8}{100}\)

\(T =\frac{600 \times 100}{3000 \times 8}\)

\(\frac{20}{8}\)

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

1,684.

Evaluate \(\frac{1.25 \times 0.025}{0.05}\), correct to 1 decimal place

A.

0.6

B.

6.2

C.

6.3

D.

0.5

Correct answer is A

\(\frac{1.25 \times 0.025}{0.05}\)

\( = \frac{125 \times 10^{-2} \times 25 \times 10^{-3}}{5 \times 10^{-2}}\)

= 125 x 5 x 10-3

= 625 x 0.001

= 0.625

= 0.6 Approx to 1 d.p.

1,685.

3 girls share a number of apples in the ration 5:3:2. If the highest share is 40 apples, find the smallest share

A.

36

B.

24

C.

16

D.

38

Correct answer is C

The sum, S of ratio is S = 5 + 3 + 2 = 10.

But highest share = \(\frac{5}{10} \times T\), where T is the total number of apples.

Thus, \(40 = \frac{5}{10} \times T\),

given 40 x 10 = 5T,

\(T = \frac{40 \times 10}{5} = 80\)

Hence the smallest share = \(\frac{2}{10} \times 80\)

= 16 apples