Direct and inverse proportionIB MYP Maths Extended: Flashcards

What these 12 flashcards ask

What is the equation for direct proportion?
What is the equation for inverse proportion?
y\propto x and y=18 when x=4. Find k.
p is inversely proportional to q and p=6 when q=5. Find k.
What does the graph of direct proportion look like?
What does the graph of inverse proportion look like?
What does doubling x do to y in direct proportion?
What does doubling x do to y in inverse proportion?
What is the unitary method?
5 cooks take 8 hours. How long do 8 cooks take?
Which is the right model: workers and time, or guests and rice?
Why can the inverse model fail for very many workers?

Exam questions on Direct and inverse proportion

$y$ is directly proportional to $x$ , and $y=18$ when $x=4$ .
Find the value of $x$ when $y=63$ .2 marks
$p$ is inversely proportional to $q$ , and $p=6$ when $q=5$ .
Find the value of $q$ when $p=4$ .2 marks
A currency exchange in Doha gives USD $68.50$ for QAR $250$ , at a fixed rate with no commission.
Find how many USD are given for QAR $1800$ .3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).