The mean of two numbers x and y is 4. Find the mean of four numbers x, 2x, y and 2y
2
4
6
8
Correct answer is C
Since the mean of the two numbers x and y is:
\(\frac{x+y}{2}\) = 4
x+y =2 * 4
x+y = 8
then we get:
\(\frac{x+2x+y+2y}{4}\)
=(\(\frac{3x+3y}{4}\))
= 3(\(\frac{x+y}{4}\)) → 3(\(\frac{8}{4}\))
= 3 * 2
= 6
A rectangle with width \(\frac{3}{4}\)cm and area 3 \(\frac{3}{8}\)cm\(^2\). Find the length
6cm
4\(\frac{1}{2}\)cm
2 \(\frac{5}{8}\)cm
12cm
Correct answer is B
The area of a rectangle = length ✕ width
: Length = area ÷ width → 3 \(\frac{3}{8}\) ÷ \(\frac{3}{4}\)
= \(\frac{27}{8}\) * \(\frac{4}{3}\)
= 4\(\frac{1}{2}\)cm
0.45
0.65
0.85
0.95
Correct answer is C
Note that the group that reads both papers is being counted twice.
(percentages add up beyond 100%)
Let M = those reading the Morning Times,
E = those reading the Evening Dispatch
P( M or E) = P(M) + P(E) – P(M and E)
= 0.45 + 0.60 – 0.20
= 0.85
Find the volume of a cone of radius 3.5cm and vertical height 12cm. [Take π = 22/7]
15.5cm\(^3\)
21.0cm\(^3\)
142cm\(^3\)
154cm\(^3\)
Correct answer is D
volume of a cone = ⅓ π r2h → \(\frac{1*22*3.5*3.5*12}{3*7}\)
= 154cm\(^3\)
5cm
7cm
10cm
15cm
Correct answer is C
Area of a trapezium = \(\frac{[a+b]h}{2}\)
105 = \(\frac{[9+12]h}{2}\) → 105 x 2 =21h
h = \(\frac{210}{21}\) → 10cm