Question

Lucy spent $\$100$ on her birthday celebration. This was $\$20$ more than one-fifth of what she she spent on shopping on her birthday. Lucy spent $\$$ on shopping on her birthday shopping.

Answer 1

Let Lucy spent $\$x$ on shopping on her birthday.
Accordingly, the amount of money, she spent on her birthday celebration $=\frac{1}{5}\times x+\$20$
Given that Lucy spent $\$100$ on her birthday celebration.
$\Rightarrow \frac{x}{5}+\$20=\$100$
Subtract $\$20$ from both the sides
$\Rightarrow \frac{x}{5}+\$20-\$20=\$100-\$20$

$\Rightarrow \frac{x}{5}=\$80$
Multiply by $5$ on both the sides
$\Rightarrow 5\times \frac{x}{5}=5\times \$80$
$\Rightarrow x=\$400$
$\therefore$ Lucy spent $\$400$ on shopping on her birthday.