Question

What percent of 2.5 hours decrease to 1 hour

Answer 1

Answer: 60% decrease

Step-by-step explanation:

How to calculate percentage decrease:

Subtract starting value minus final value

Divide that amount by the absolute value of the starting value

Multiply by 100 to get percent decrease

If the percentage is negative, it means there was an increase and not an decrease.

Percentage Decrease Formula

You can use the percentage decrease formula for any percent decrease calculation:

Percentage Decrease=Starting Value−Final Value|Starting Value|×100

Example Problem: Percentage Decrease

You have a lamp with a 60-watt traditional light bulb. Your lamp uses 60 watts of electricity per hour. You're considering replacing the bulb with an LED light bulb that uses 8 watts of electricity per hour. What is the percentage decrease in the lamp's hourly energy use if you switch to an LED light bulb?

Percentage Decrease = [ (Starting Value - Final Value) / |Starting Value| ] × 100

60 - 8 = 52

52 / 60 = 0.8667

0.8667 × 100 = 86.67%

So if you switch to an LED light bulb your lamp will use 86.67% less energy per hour.

Related Calculators

Answer 2

40%

Step-by-step explanation:

Whenever we find "x" percent of a number, we simply multiply by "x/100", because "percent" just means "per 100".

We can divide the 2.5, by 100 to see how many "groups" of 100 are in 2.5, which gets us, 0.025.

Now we multiply this by some value, which will be our percent, to get "1"

So we have the equation:
`0.025 * x = 1`

Dividing both sides by 0.025 gives us:
`x=40`

so our percentage would be 40.

But generally whenever you solve these problems you convert the "percentage" to a "decimal" by dividing the percentage by 100.

So finding "x" percent of "a", can be calculated by:
`a*(x)/(100)`

and from here you would calculate the value with the givens.