Question

In 1945, a microwave cost $435. Today, a microwave costs $130. What is the percent of change?

Answer 1

29.89%

Explanation:

Step 1: We assume that 435 is 100% since it is our output value.

Step 2: We next represent the value we seek with
`$x$`.

Step 3: From step 1, it follows that
`$100\%=435$`.

Step 4: In the same vein,
`$x\%=130$`.

Step 5: This gives us a pair of simple equations:

`100\%=435(1)\\\\x\%=130(2)`

Step 6: By simply dividing equation 1 by equation 2 and taking note of the fact that both the LHS (left-hand side) of both equations have the same unit (%); we have

`$(100\%)/(x\%)=(435)/(130)$`

Step 7: Taking the inverse (or reciprocal) of both sides yields

`(x\%)/(100\%)=(130)/(435)\\\\\Rightarrow x=29.89\%`

Therefore,
`$130$` is
`$29.89\%$` of
`$435$`.