NECO Mathematics Past Questions & Answers - Page 9

41.

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 

42.

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.

43.

If 2x : ( x + 1) = 3 : 2, what is the value of x?

A.

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

B.

1

C.

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

D.

3

E.

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

Correct answer is D

No explanation has been provided for this answer.

44.

Two fair dice are tossed together once. What is the probability of getting a total of at least 9 from the outcome?

A.

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

B.

\(\frac{1}{6}\)

C.

\(\frac{5}{18}\)

D.

\(\frac{1}{3}\)

E.

\(\frac{13}{18}\)

Correct answer is C

No explanation has been provided for this answer.