Jamb Mathematics 1981 Past Questions and Answers

Question 36:

• JAMB 1981

If b = a + cp and r = ab + \(\frac{1}{2}\)cp², express b² in terms of a, c, r.

A. B² = aV + 2cr
B. B² = ar + 2c²r
C. B² = a² = \(\frac{1}{2}\) cr²
D. B² = \(\frac{1}{2}\)ar² + c
E. B² = 2cr - a²

Question 37:

• JAMB 1981

Multiply x² + x + 1 by x² - x + 1

A. X⁴ - x + x²
B. X⁴ - x² + x²
C. X⁴ + x² + 1
D. X⁴ + x²

Question 38:

• JAMB 1981

A baking recipe calls for 2.5kg of sugar and 4.5kg of flour. With this recipe some cakes were baked using 24.5kg of a mixture of sugar and flour. How much sugar was used?

A. 12.25kg
B. 6.75kg
C. 8.75kg
D. 15.75kg
E. 8.25kg

Question 39:

• JAMB 1981

The difference between 4\(\frac{5}{7}\) and 2\(\frac{1}{4}\) greater by

A. \(\frac{23}{28}\)
B. \(\frac{24}{28}\)
C. \(\frac{50}{56}\)
D. \(\frac{27}{28}\)
E. \(\frac{48}{56}\)

Question 40:

• JAMB 1981

What is the size of an exterior angle of a regular pentagon?

A. 36^o
B. 60^o
C. 72^o
D. 120^o
E. 360^o