Question

The battery on McKenzie's old computer can last for 4 1/5 hours. She bought a new computer that has a battery that can last 40% longer. How long can the battery on McKenzie's new computer last?

Answer 1

`5(22)/(25)\ hours`

Explanation:

we know that

`4(1)/(5)\ hours=(4*5+1)/(5)=(21)/(5)\ hours`
`100\%+40\%=140\%=(140)/(100)`

Let

x ------> new battery life

The equation that represent this situation is

`x=((140)/(100))((21)/(5))=(2,940)/(500)\ hours`

convert to mixed number

`(2,940)/(500)=(2,500)/(500)+(440)/(500)=5(22)/(25)\ hours`