55
Direct and Inverse Proportion
Qi
Q2
Q3
Q4
Q5
Q6
Q8
Q9
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Q11
a)
y is directly proportional to x. If y = 5 when x is 25, find y when x is 100. y is directly proportional to x. If y is 1.2 when x is 2.5, find the value of y when x = 3.75. Complete the following tables of values where y is always directly proportional to x.
4
6
10
•
b) c) X 6 9
9
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x MIME y ic,
If y = 3 when x = 8 and y is inversely proportional to x, find the value of y when x = 12.
If y and x vary inversely, and y = 12 when x = 3 find: a) the value of x when y = 9 b) the value of y when x = 6.
The length of a squid is proportional to the number of raccoons it has eaten. A squid 890 cm long was found to have eaten 58 raccoons in its lifetime. Calculate: a) the length of a squid that had eaten 29 raccoons b) the number of raccoons a 614 cm long squid has eaten.
Some scientists are building a telescope to view a space dragon. They know the length is proportional to the magnification and calculate that a telescope 3 metres long will make the dragon appear 50 times larger. a) How long would it need to be to make the dragon appear: i) 75 times larger? ii) 220 times larger? b) They find the space dragon looks too scary so close up. How long does the telescope need to be to make the dragon appear 15 times laridietr? ap IP
If y a x and y = 132 when x = 10, find the value of y when x = 14. If y x and y = 117 when x= 45, find the value of x when y = 195. If y oc and x = 4 when y = 5, find the value of x when y = 10.
Given that y oc —1 complete this table of values. x '
y
1
2
3
4
5 9.6
6
\\111 1 1111111iii//__ Put the numbers into the equation y = k/x to find the value of k. — Then you can find the rest of the ys. ------ ///11 n1111111111 11 \\\
Make sure you know the 4 main details about Direct and Inverse Proportion: 1) what happens when one quantity increases, 2) the graph, 3) the table of values, 4) whether it's the ratio or the product that's the same for all values.
SECTION THREE — ALGEBRA