15 minutes
<h3>
Further explanation</h3>
<u>Given:</u>
- Jenny has an hour before its bedtime.
- Jenny spends
of an hour texting a friend and
of the remaining time brushing her teeth and putting on her pajamas. - She spends the rest of the time reading her book.
<u>Question:</u>
How long did Jenny read?
<u>The Process:</u>
Step-1: We need to calculate the time of texting a friend in minutes.
Recall that ![\boxed{1 \ hour = 60 \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B1%20%5C%20hour%20%3D%2060%20%5C%20minutes%7D)
![\boxed{\frac{3}{5} \ hour = \ ? \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cfrac%7B3%7D%7B5%7D%20%5C%20hour%20%3D%20%5C%20%3F%20%5C%20minutes%7D)
![\boxed{\frac{3}{5} \ hour = \frac{3}{5} \times 60 \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cfrac%7B3%7D%7B5%7D%20%5C%20hour%20%3D%20%5Cfrac%7B3%7D%7B5%7D%20%5Ctimes%2060%20%5C%20minutes%7D)
We crossed out 5 and 60, i.e., ![\boxed{60 \div 5 = 12}](https://tex.z-dn.net/?f=%5Cboxed%7B60%20%5Cdiv%205%20%3D%2012%7D)
![\boxed{\frac{3}{5} \ hour = 3 \times 12 \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cfrac%7B3%7D%7B5%7D%20%5C%20hour%20%3D%203%20%5Ctimes%2012%20%5C%20minutes%7D)
Therefore,
![\boxed{\boxed{ \ \frac{3}{5} \ hour = 36 \ minutes \ }}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cboxed%7B%20%5C%20%5Cfrac%7B3%7D%7B5%7D%20%5C%20hour%20%3D%2036%20%5C%20minutes%20%5C%20%7D%7D)
Step-2: Let us calculate the remaining time.
![\boxed{60 \ minutes - 36 \ minutes = 24 \ minutes }](https://tex.z-dn.net/?f=%5Cboxed%7B60%20%5C%20minutes%20-%2036%20%5C%20minutes%20%3D%2024%20%5C%20minutes%20%7D)
Step-3: Jenny spends
of the remaining time brushing her teeth and putting on her pajamas.
![\boxed{\frac{3}{8} \times 24 \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cfrac%7B3%7D%7B8%7D%20%5Ctimes%2024%20%5C%20minutes%7D)
We crossed out 8 and 24, i.e., ![\boxed{24 \div 8 = 3}](https://tex.z-dn.net/?f=%5Cboxed%7B24%20%5Cdiv%208%20%3D%203%7D)
![\boxed{= 3 \times 3 \ minutes}](https://tex.z-dn.net/?f=%5Cboxed%7B%3D%203%20%5Ctimes%203%20%5C%20minutes%7D)
![\boxed{\boxed{ \ 9 \ minutes \ }}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cboxed%7B%20%5C%209%20%5C%20minutes%20%5C%20%7D%7D)
Step-4: Let us calculate how long Jenny read for the rest of time.
![\boxed{24 \ minutes - 9 \ minutes = 15 \ minutes }](https://tex.z-dn.net/?f=%5Cboxed%7B24%20%5C%20minutes%20-%209%20%5C%20minutes%20%3D%2015%20%5C%20minutes%20%7D)
Thus, Jenny spent 15 minutes reading a book before its bedtime.
- - - - - - - - - -
Quick Steps:
Let us calculate how long Jenny read for the rest of time.
![\boxed{ \ = \bigg(1 - \frac{3}{8} \bigg) \times \bigg(1 - \frac{3}{5} \bigg) \times 60 \ minutes \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%3D%20%5Cbigg%281%20-%20%5Cfrac%7B3%7D%7B8%7D%20%5Cbigg%29%20%5Ctimes%20%5Cbigg%281%20-%20%5Cfrac%7B3%7D%7B5%7D%20%5Cbigg%29%20%5Ctimes%2060%20%5C%20minutes%20%5C%20%7D)
![\boxed{ \ = \frac{5}{8} \times \frac{2}{5} \times 60 \ minutes \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%3D%20%5Cfrac%7B5%7D%7B8%7D%20%5Ctimes%20%5Cfrac%7B2%7D%7B5%7D%20%5Ctimes%2060%20%5C%20minutes%20%5C%20%7D)
![\boxed{ \ = \frac{10}{40} \times 60 \ minutes \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%3D%20%5Cfrac%7B10%7D%7B40%7D%20%5Ctimes%2060%20%5C%20minutes%20%5C%20%7D)
![\boxed{ \ = \frac{1}{4} \times 60 \ minutes \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%3D%20%5Cfrac%7B1%7D%7B4%7D%20%5Ctimes%2060%20%5C%20minutes%20%5C%20%7D)
![\boxed{\boxed{ \ 15 \ minutes \ }}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Cboxed%7B%20%5C%2015%20%5C%20minutes%20%5C%20%7D%7D)
<h3>Learn more</h3>
- How much water did they spill altogether on their way down the hill? brainly.com/question/429584#
- How much fabric is used for each pillow? brainly.com/question/9215374
- How many times does he switch strokes during the race? brainly.com/question/11494844
Keywords: Jenny, has an hour, before its bedtime, spends 3/5 of an hour, texting a friend, 3/8 of the remaining time, brushing her teeth, putting on her pajamas, reading her book