Jamb Mathematics Past Questions For Year 1981
Question 11
Marks scored by some children in an arithmetic test are:5, 3, 6, 9, 4, 7, 8, 6, 2, 7, 8, 4, 5, 2, 1, 0, 6, 9, 0, 8.
The arithmetic mean of the marks is
- A. 6
- B. 5
- C. 8
- D. 7
- E. 10
Question 12
The weights of 30 new-born babies are given as follow: 6, 9, 5, 7, 6, 7, 5, 8, 9, 5, 7, 5, 8, 7, 8, 7, 5, 6, 5, 7, 6, 9, 9, 7, 8, 8, 7, 8, 9, 8. The mode is
- A. 6
- B. 5
- C. 8
- D. 7
- E. 10
Question 13
If \(\sin x° = \frac{a}{b}\), what is \(\sin (90 - x)°\)?
- A. \(\frac{\sqrt{b^2 - a^2}}{b}\)
- B. 1\(\frac{-a}{b}\)
- C. \(\frac{b^2 - a^2}{b}\)
- D. \(\frac{a^2 - b^2}{b}\)
- E. \(\sqrt{b^2 - a^3}\)
Question 14
7 pupils of average age 12 years leave a class of 25 pupils of average age 14 years. If 6 new pupils of average age 11years join the class, what is the average age of the pupils now in the class?
- A. 13years
- B. 12 years 7\(\frac{1}{2}\) months
- C. 13 years 5 months
- D. 13 years 10 months
- E. 11 years
Question 15
A sum of money invested at 5% per annum simple interest amounts to $285.20 after 3 years. How long will it take the same sum to amount to $434.00 at 7\(\frac{1}{2}\)% per annum simple interest?
- A. 7\(\frac{1}{2}\) years
- B. 10 years
- C. 5 years
- D. 12 years
- E. 14 years
