Question

Please help me this looks easy but I don’t understand it tho

Answer 1

Let's call the unknown amount of money x

Betty spend 5/12 of her money (5/12)x and had 42 dollars left. Translated,

$x - \frac 5{12} x = 42$

Solving,

$x(1 - \frac 5{12}) = 42$

$\frac{7}{12} x = 42$

$x = \dfrac{12}{7} \cdot 42 = 72$

Answer: $72