WAEC Past Questions and Answers - Page 3945

19,721.

The vessel that carries blood from the heart to the lungs is called an artery because it

A.

contains oxygenated blood

B.

contains more blood than the other vessels

C.

carries blood away from the heart

D.

has thick inelastic wall

Correct answer is C

No explanation has been provided for this answer.

19,722.

Water flows from a tap into cylindrical container at the rate 5πcm\(^3\) per second. If the radius of the container is 3cm, calculate the level of water in the container at the end of 9 seconds.

A.

2cm

B.

5cm

C.

8cm

D.

15cm

Correct answer is B

Volume of water after 9 seconds = \(5\pi \times 9 = 45\pi cm^3\)

Volume of cylinder = \(\pi r^2 h\)

\(\therefore \pi r^2 h = 45\pi\)

\(\pi \times 3^2 \times h = 45\pi\)

\(\implies 9h = 45 \)

\(h = 5 cm\)

(where h = height of the water after 9 secs)

19,723.

The height and base of a triangle are in ratio 1:3 respectively. If the area of the triangle is 216 cm\(^2\), find the length of the base.

A.

24cm

B.

36cm

C.

72cm

D.

144cm

Correct answer is B

Area = \(\frac{1}{2} \times base \times height\)

\(height : base = 1 : 3\)

\(\implies base = 3 \times height\)

Let height = h;

Area = \(\frac{1}{2} \times 3h \times h = 216\)

\(3h^2 = 216 \times 2 = 432\)

\(h^2 = \frac{432}{3} = 144\)

\(h = \sqrt{144} = 12.0 cm\)

\(\therefore base = 3 \times 12 = 36 cm\)

19,724.

One of the similarities between algae and mosses is their possession of

A.

chlorophyll

B.

stem

C.

leaves

D.

roots

Correct answer is A

No explanation has been provided for this answer.

19,725.

A car travel at x km per hour for 1 hour and at y km per hour for 2 hours. Find its average speed

A.

\(\frac{2x + 2y}{3}kmh^{-1}\)

B.

\(\frac{x + y}{3}kmh^{-1}\)

C.

\(\frac{x + 2y}{3}kmh^{-1}\)

D.

\(\frac{2x + y}{3}kmh^{-1}\)

Correct answer is C

Travelled x km/h for 1 hour \(\therefore\) traveled x km in the first hour.

Traveled y km/h for 2 hours \(\therefore\) traveled 2y km in the next 2 hours.

Average speed = \(\frac{x + 2y}{1 + 2}\)

= \(\frac{x + 2y}{3} kmh^{-1}\)