NECO Past Questions and Answers - Page 154

766.

Find the 19th term of the A.P. \(\frac{5}{6}\), \(\frac{8}{6}\), \(\frac{11}{6}\).................

A.

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

B.

9

C.

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

D.

9\(\frac{5}{6}\)

E.

10

Correct answer is D

first term (a) = \(\frac{5}{6}\)

common difference =   \(\frac{8}{6}\) - \(\frac{5}{6}\) → \(\frac{3}{6}\) or \(\frac{1}{2}\)

A.P formula → T\(_n\) = a + (n - 1)d
T\(_n\) = \(\frac{5}{6}\) + (19 - 1)\(\frac{1}{2}\)
T\(_n\) = \(\frac{5}{6}\) + 9

→ 9\(\frac{5}{6}\)

767.

Mr Aborowa bought a car for N200,000.00 and later sold it for N170,000.00. What is the percentage loss?

A.

11.60%

B.

7.60%

C.

15%

D.

17.65%

Correct answer is C

Using these:

Loss = C.p - S.p

: Percentage Loss = ( Loss X 100) ÷ C.p

=15 %

768.

If s = \(\sqrt{(\frac{a^2}{x^2} - \frac{b^2}{y^2})}\)what does y equal?

A.

\(\sqrt{\frac{(b^2 - a^2)}{(s^2 - x^2)}}\)

B.

\(\sqrt{\frac{(b^2 - a^2)}{(s^2 \times 2)}}\)

C.

\(\sqrt{\frac{x^2 - a^2 - b^2}{s}}\)

D.

\(\frac{x^2 - a^2 - b^2}{s}\)

E.

\(\sqrt{\frac{(b^2 x^2)}{(a^2 - s^2 x^2)}}\)

Correct answer is E

s = \(\sqrt{(\frac{a^2}{x^2} - \frac{b^2}{y^2})}\)

s\(^2\) = \(\frac{a^2}{x^2} - \frac{b^2}{y^2}\)

\(\frac{b^2}{y^2}\) = \(\frac{a^2}{x^2}\) - s\(^2\)

\(\frac{b^2}{y^2}\) = \(\frac{a^2 - s^2 x^2}{x^2}\)

\(\frac{1}{y^2}\) = \((\frac{a^2 - s^2 x^2}{x^2}) \times \frac{1}{b^2}\)

\(\frac{1}{y^2}\) = \(\frac{a^2 - s^2 x^2}{b^2 x^2}\)

\(\therefore\) y\(^2\) = \(\frac{b^2 x^2}{a^2 - s^2 x^2}\)

y = \(\sqrt{\frac{b^2 x^2}{a^2 - s^2 x^2}}\)

769.

A body which weighs 50N in air displaces 3.7kg of water when partially immersed in water. Calculate the upthrust on the body?

A.

8.7N

B.

37.0N

C.

87.0N

D.

13.0N

Correct answer is B

Upthrust = Weight or water displaced
= 3.7 x 10 = 37N

770.

The best method of production in an under populated country is

A.

Labour-extensive

B.

Land-intensive

C.

Capital-intensive

D.

Labour-intensive

Correct answer is C

No explanation has been provided for this answer.