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Direct & inverse proportion
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Browse Direct & inverse proportion
42 questions at your level
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Level 1
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Level 5
Direct proportion
15 questions
Lesson
Not started
Mark as done
y
y
y
is directly proportional to
x
x
x
. When
x
=
20
x = 20
x
=
20
,
y
=
15
y = 15
y
=
15
.
When
x
=
c
x = c
x
=
c
,
y
=
c
−
2
y = c - 2
y
=
c
−
2
. Work out the value of
c
c
c
.
●●●●●
Level 5
3 marks
Start
→
Mark as done
y
y
y
is directly proportional to
x
x
x
. When
x
=
12
x = 12
x
=
12
,
y
=
9
y = 9
y
=
9
.
When
x
=
c
x = c
x
=
c
,
y
=
c
−
4
y = c - 4
y
=
c
−
4
.
Work out the value of
c
c
c
.
●●●●●
Level 5
3 marks
Start
→
Inverse proportion
16 questions
Lesson
Not started
Mark as done
4 identical pumps can empty a tank in 18 hours.
All 4 pumps run for the first 6 hours, and then one pump breaks down. How many more hours do the remaining 3 pumps take to finish emptying the tank?
●●●●●
Level 5
4 marks
Start
→
Mark as done
A job takes
10
10
10
workers exactly
12
12
12
days.
All
10
10
10
workers work for the first
4
4
4
days. Then
2
2
2
workers leave, and the remaining
8
8
8
finish the job.
Work out the
total
number of days the job takes.
●●●●●
Level 5
4 marks
Start
→
Mark as done
P
P
P
is inversely proportional to
q
q
q
.
q
q
q
is directly proportional to the cube root of
r
r
r
.
When
q
=
4
q = 4
q
=
4
,
P
=
15
P = 15
P
=
15
When
q
=
10
q = 10
q
=
10
,
r
=
125
r = 125
r
=
125
Find the value of
r
r
r
when
P
=
40
P = 40
P
=
40
(5 marks)
●●●●●
Level 5
5 marks
Start
→
Proportion with squares, cubes and roots
14 questions
Lesson
Not started
Mark as done
a
a
a
is directly proportional to the square of
b
b
b
, and
b
b
b
is directly proportional to the square root of
c
c
c
.
When
c
=
16
c = 16
c
=
16
,
b
=
12
b = 12
b
=
12
. When
b
=
12
b = 12
b
=
12
,
a
=
36
a = 36
a
=
36
.
(a)
Find a formula for
a
a
a
in terms of
c
c
c
.
(b)
Work out the value of
a
a
a
when
c
=
64
c = 64
c
=
64
.
●●●●●
Level 5
4 marks
Start
→
Mark as done
a
a
a
is directly proportional to the
square
of
b
b
b
: when
b
=
2
b = 2
b
=
2
,
a
=
16
a = 16
a
=
16
.
b
b
b
is directly proportional to the
cube root
of
c
c
c
: when
c
=
8
c = 8
c
=
8
,
b
=
4
b = 4
b
=
4
.
Work out the value of
a
a
a
when
c
=
27
c = 27
c
=
27
.
●●●●●
Level 5
4 marks
Start
→
Mark as done
P
P
P
is inversely proportional to
q
q
q
.
q
q
q
is directly proportional to the cube root of
r
r
r
.
When
q
=
4
q = 4
q
=
4
,
P
=
15
P = 15
P
=
15
When
q
=
10
q = 10
q
=
10
,
r
=
125
r = 125
r
=
125
Find the value of
r
r
r
when
P
=
40
P = 40
P
=
40
(5 marks)
●●●●●
Level 5
5 marks
Start
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