Question

Brendan set his watch at 8:30 A.M. At 2:30 PM. he noticed his watch had lost 5 minutes. How many minutes in all did his watch lose by 8:30 A.M. the next day?

Answer 1

The difference between the first two times is 6 hours.

Explanation:

In that period it lost 5 minutes.
The next difference between 8:30am and the same time next morning is 24 hours. This is 4 times as much, so the watch will have lost `4xx5min=20min`

This watch needs a serious overhaul!

Answer 2

To find out how many minutes his watch lost, you'll have to find out the time period b/w `8:30 A.M. and 2:30 P.M.`

It is of course 6 hours,

So, we know that per every 6 hours, his watch loses 5 minutes,

The difference between 8:30 AM of a day and 8:30 AM of the next day is 24 hours (everybody knows that)

We can do it in the proportional form(it is one of the many ways)
Per every 6 hours, he lost 5 minutes, Per every 24 hours, how many minutes will he lose?
The proportion will be
`6:5::24:x`
That is,
`6/5=24/x`

Multiply both sides by `x`
`6/5x=24/cancelx cancel x`
`(6x)/5=24`
Multiply both sides by 5,
`(6x)/cancel 5 cancel 5=24 xx 5`
`6x=120`
`x=120/6`
`x=20`
He loses 20 minutes every day.