Question

.You saved $200 on your new laptop because you bought it online. If this was a 20% savings from the original price, find the originalcost of the laptop.The original cost of the laptop was

Answer 1

so, the original cost was $100

Explanation

the easiest way to solve this is by using a rule of three

then

Step 1

Let

orginal price=100% = unknow value= x

aved= 20%=$200,

Step 2

make the proportions and solve for x

$\begin{gathered} \text{if } \\ x\rightarrow100 \\ \text{then} \\ 200\rightarrow20 \\ \end{gathered}$

the ratios are equals, so the proportion is

$\frac{x}{100}=\frac{200}{20}$

finally, isolate x

$\begin{gathered} \frac{x}{100}=\frac{200}{20} \\ cross\text{ multiply} \\ 20\cdot x\text{=10}0\cdot200 \\ 20x=20000 \\ \text{divide both sides by 20} \\ \frac{20x}{20}=\frac{20000}{200} \\ x=20 \\ x=100 \end{gathered}$

so, the original cost was $100

I hope this helps you