NECO Past Questions and Answers - Page 126

626.

The chances of Usman and Dele passing a Mathematics test are 12 and 13 respectively. What is the probability that neither of them passes the test?

A.

\(\frac{3}{5}\)

B.

\(\frac{2}{5}\)

C.

\(\frac{4}{15}\)

D.

\(\frac{1}{5}\)

E.

\(\frac{2}{15}\)

Correct answer is C

No explanation has been provided for this answer.

628.

A sector of angle 120° is cut out from a circle of radius 13.5cm. what area of the circle is remaining ? (π = \(\frac{22}{7}\))

A.

14.1cm2

B.

95.5cm2

C.

190.9cm2

D.

381.9cm2

E.

763.7cm2

Correct answer is D

No explanation has been provided for this answer.

629.

Twenty girls and y boys sat on an examination. The mean marks obtained by the girls and boys were 52 and 57 respectively. if the total score for both girls and boys was 2750, find y.

A.

51

B.

48

C.

30

D.

25

E.

18

Correct answer is C

Let the total score for the girls and the boys be A and B respectively.

\(\frac{A}{20} = 52 \implies A = 52 \times 20\)

A = 1040

\(\frac{B}{y} = 57 \implies B = 57y\)

1040 + 57y = 2750

57y = 2750 - 1040

57y = 1710

y = \(\frac{1710}{57}\)

y = 30 

630.

If y2+ 14y + k is a perfect square, then k =

A.

4

B.

7

C.

28

D.

49

E.

196

Correct answer is D

No explanation has been provided for this answer.