Question

Brenda found a deal for a kayak trip to see the bioluminescent jellyfish in the Indian

River Lagoon. The deal said it was 30% of the regular price. Shawn paid $250 for 5
adults.
Determine the regular cost of the kayak trip for 1 adult.

Answer 1

the regular price for five adults was really "x", which oddly enough is the 100%.

now, Shawn, not sure how he relates to Brenda btw, paid $250, but that was a discounted price by 30%, so Shawn really paid 100% - 30% = 70%, so the 250 bucks is really just the 70% of the regular price.

if we know that 250 is the 70%, what the heck is "x"?

`\begin{array}{ccll} amount&\%\\ \cline{1-2} x & 100\\ 250& 70 \end{array} \implies \cfrac{x}{250}~~=~~\cfrac{100}{70} \\\\\\ \cfrac{ x }{ 250 } ~~=~~ \cfrac{ 10 }{ 7 }\implies 7x=2500\implies x=\cfrac{2500}{7}\leftarrow \textit{that's for 5 adults} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{now, just for one adult}}{\cfrac{2500}{7}/ 5}\implies \cfrac{2500}{7}/ \cfrac{5}{1}\implies \cfrac{2500}{7}\cdot \cfrac{1}{5}\implies \cfrac{500}{7} ~~ \approx ~~ \text{\LARGE 71.43}`