JAMB Mathematics Past Questions & Answers - Page 68

336.

A man's initial salary is N540.00 a month and increases after each period of six months by N36.00. Find his salary in the eight month of the third year.

A.

N828.00

B.

N756.00

C.

N720.00

D.

N684.00

Correct answer is C

Since the salary increases by #36 after every 6 months

: 2 years and 8 months imply an increase of five times only:

36 * 5 →  #180

 His salary then = initial salary + increment

  = 540 + 180

  = #720

  Answer is C

337.

Find the equation of the line through (5,7) parallel to the line 7x + 5y = 12 

A.

5x + 7y = 20

B.

x + 5y = 70

C.

xy = 7

D.

15x + 17y = 90

Correct answer is B

No explanation has been provided for this answer.

338.

Divide the L.C.M of 48, 64 and 80 by their H.C.F

A.

20

B.

30

C.

48

D.

60

Correct answer is D

No explanation has been provided for this answer.

339.

A room is 12m long, 9m wide and 8m high. Find the cosine of the angle which a diagonal of the room makes with the floor of the room.

A.

\(\frac{15}{17}\)

B.

\(\frac{9}{17}\)

C.

\(\frac{8}{15}\)

D.

\(\frac{12}{17}\)

Correct answer is A

Given length of the room = 12m; breadth = 9m and height = 8m.

The room is a cuboid in shape, therefore the length of the diagonal = \(\sqrt{l^2 + b^2 + h^2}\)

= \(\sqrt{12^2 + 9^2 + 8^2}\)

=\(\sqrt{289}\)

= 17m.

The diagonal makes an angle with the diagonal of the floor: \(\sqrt{12^2 + 9^2}\)

= \(\sqrt{225}\)

= 15m

The cosine of the angle that the diagonal makes with the floor (\(\theta\)) = \(\frac{15}{17}\).