HKDSE Maths MCQ Speed Training 3 (32 mins)

[Ref.: HKDSE 2014 Q.28 (72%)]

The mean height of 30 boys and 20 girls is 154 cm. If the mean height of the boys is 165 cm, then the mean height of the girls is

• A. 137.5 cm.

• B. 140 cm.

• C. 150 cm.

• D. 153 cm.

[Ref.: HKDSE 2019 Q.28 (66%)]

Two numbers are randomly drawn at the same time from six cards numbered 1, 2, 3, 3, 4 and 7 respectively. Find the probability that the sum of the numbers drawn is an odd number.

• A. I and II only

• B. I and III only

• C. II and III only

• D. I, II and III

• A. - k³ .

• B. - k³ + 2k .

• C. - k³ + 6k .

• D. - k³ + 8k .

[Ref.: HKDSE 2016 Q.31 (61%)]

The L.C.M. of 6a²b³, 9a⁴b² and 12a⁵ is

• A. 3a² .

• B. 3a²b² .

• C. 36a⁵b³ .

• D. 72a¹¹b⁵ .

[Ref.: HKDSE 2012 Q.31 (55%)]

The H.C.F. and the L.C.M. of 3 expressions are a²b and 9a⁵b³c² respectively. If the first and the second expressions are 3a²b²c and a³b³c² respectively, then the third expression is

• A. a³b²c .

• B. 3a²b² .

• C. 9a⁵b .

• D. 9a⁵b³c .

[Ref.: HKDSE 2014 Q.33 (54%)]

Which of the following is the greatest?

• A. 235³⁵² .

• B. 253³²⁵ .

• C. 523²⁵³ .

• D. 532²³⁵ .

[Ref.: HKDSE 2013 Q.31 (52%)]

The L.C.M. of 4a² - 16a + 16, 2a² - 8, a³ - 8 is

• A. a - 2 .

• B. 4(a - 2)²(a + 2)(a² - 2a + 4) .

• C. 4(a - 2)²(a + 2)(a² + 2a + 4) .

• D. 8(a - 2)⁴(a + 2)(a² + 2a + 4) .