ITMC 2018 Grade 8 National Preliminary set01 Question 1

Question 1

Printed positive marks are preserved per question. The source uses different blank-answer and incorrect-answer rules by section, including an optional bonus penalty; the import does not reproduce that complete official scoring scheme.

What is the value of $\dfrac{2^{20}+2^{18}}{2^{19}+2^{18}}$?

$4/3$
$2^{36}$
2
$2^{18}$
$5/3$