Question

The student has just finished learning the first 15 percent of the words. (Give your answers correct to at least three decimal places.) How long would it take to learn 15 percent of the remaining words

Answer 1

`0.85t`

Explanation:

let
`x` be the number of words and
`t` the time it takes to read 15% of the words.

First we find 15% of the remaining words.

`Words \ read=x-0.15x=0.85x\\15\% of Remainder=0.15* 0.85x=0.1275x`

Therefore to find time for next 15% we equate remainder to initial time:

If

`0.15x=t\\0.1275x=?`

Cross multiply:

`=(0.1275x*t)/(0.15x)\\=0.85t`

Hence it takes
`0.85t` to read next 15% of the remaining words.