EduNinja

[Maximum number: 5]

(a)

y is directly proportional to $(x+3)^3$ .
When x=2, y=13.5.
Find x when y=108.
x=

[ 3 ]

7
M1 for $y=k(x+3)^3$ or better
M1 for $108=\text{their }k(x+3)^3$

(b)

g is inversely proportional to the square of d.
When d is halved, the value of g is multiplied by a factor n.
Find n.

[ 2 ]

4
M1 for $\left(\frac12\right)^2$ oe or equivalent inverse-square working

[Maximum number: 2]

The energy of a moving object is directly proportional to the square of its speed.

The speed of the object is increased by 30%.
Calculate the percentage increase in the energy of the object.

69
M1 for figs $13^2$ oe

[Maximum number: 2]

y is inversely proportional to the square of (x+3).
When x=5, y=0.375.
Find y in terms of x.
y=

$y=\frac{24}{(x+3)^2}$ oe final answer
M1 for $y=\frac{k}{(x+3)^2}$

CAIE IGCSE Mathematics Extended E2.8 Proportion Topic Practice

Question 1

Question (a)

Question (b)

Question 2

Question 3