$${\textbf{Step -1: Finding the probability of getting an odd number}}$$
$${\text{Let the probability of having an odd number is P}}\left( {\overline E } \right) = x$$
$$\because {\text{P}}\left( E \right) + P\left( {\overline E } \right) = 1.$$
$$ \Rightarrow \dfrac{7}{{10}} + P\left( {\overline E } \right) = 1$$
$$ \Rightarrow P\left( {\overline E } \right) = 1 - \dfrac{7}{{10}}$$
$$ \Rightarrow P\left( {\overline E } \right) = \dfrac{{10 - 7}}{{10}} = \dfrac{3}{{10}}$$
$${\text{Hence, probability of having an odd number is }}\dfrac{3}{{10}}.$$
$${\textbf{Step -2: Finding how many times the odd number occurs when dice is thrown 80 times.}}$$
$$\because P\left( {\overline E } \right) = \dfrac{3}{{10}}$$
$$ \Rightarrow \dfrac{{{\text{Number of favourable outcomes}}}}{{{\text{Total outcomes}}}} = \dfrac{3}{{10}}$$
$$\left( {{\textbf{Using the formula: Probability = }}\dfrac{{{\textbf{Number of favorable outcomes}}}}{{{\textbf{Total outcomes}}}}} \right)$$
$$ \Rightarrow \dfrac{{{\text{Number of favourable outcomes}}}}{{80}} = \dfrac{3}{{10}}$$ $$\left( {\because {\textbf{Dice is thrown 80 times}}} \right)$$
$$ \Rightarrow {\text{Number of favourable outcomes}} = \dfrac{{3 \times 80}}{{10}} = 24$$
$${\text{Hence, 24 times odd number will occur when dice is thrown 80 times}}{\text{.}}$$
$${\textbf{Hence,24 times odd number will occur when dice is thrown 80 times.}}$$