JAMB Mathematics Past Questions & Answers - Page 291

1,451.

Express the product of 0.0014 and 0.011 in standard form

A.

1.54 x 10-2

B.

1.54 x 10-3

C.

1.54 x 10-4

D.

1.54 x 10-5

Correct answer is D

\(0.0014 = 1.4 \times 10^{-3}\)

\(0.011 = 1.1 \times 10^{-2}\)

\(\therefore 0.0014 \times 0.011 = 1.4 \times 10^{-3} \times 1.1 \times 10^{-2}\)

= \(1.54 \times 10^{-5}\)

1,452.

A worker's present salary is N24,000 per annum. His annual increment is 10% of his basic salary. What would be his annual salary at the beginning of the third year?

A.

N28,800

B.

N29,040

C.

N31,200

D.

N31,944

Correct answer is B

Present salary = N24,000.

Increment after first year = \(\frac{10}{100} \times N24,000 = N2,400\)

Salary at the beginning of second year = N(24,000 + 2,400)

= N26,400.

Increment after second year = \(\frac{10}{100} \times N26,400 = N2,640\)

Salary at the beginning of third year = N(26,400 + 2,640)

= N29,040.

\(\therefore\) His salary at the beginning of the third year = N29,040.

 

1,453.

The length of a notebook 15cm, was measured as 16.8cm. Calculate the percentage error to 2 significant figures.

A.

12.00%

B.

11.00%

C.

10.71%

D.

0.12%

Correct answer is A

Error = (16.8cm - 15cm = 1.8cm\)

\(\text{% error} = \frac{1.8}{15} \times 100% = \frac{180}{15}\)

= \(12.00%\)

1,454.

Convert 3.1415926 to 5 decimal places

A.

3.14160

B.

3.14159

C.

0.31415

D.

3.14200

Correct answer is B

3.1415926 \(\approxeq\) 3.14159 (to 5 d.p)

1,455.

Calculate \(3310_5 - 1442_5\)

A.

13135

B.

21315

C.

43025

D.

11035

Correct answer is A

\(3310_{5} - 1442_{5} = 1313_{5}\)

You can either do a direct subtraction (which is easier), or convert both numbers in base 10, subtract and convert back to base 5 (if you're not sure).