Question

Find two different sets of coins that each make 120% of a dollar, where no type of coin is in both sets

Answer 1

First we have to find how much is the 120% of a dollar so we can made a rue of 3

$\begin{gathered} 1\to100 \\ x\to120 \end{gathered}$

and the equation will be:

$x=\frac{1\cdot120}{100}=1.20$

So to have 1.20 dollars we can have:

option 1: 1 coin of 1 dollar and two dimes

option 2: 1 coin of a dollar and 4 coins of 5 cents.