Word problem concerning fraction: "A mobile telecommunications company charges 15 k/sec to encourage..."

[chijioke]

Beginning with the (a) part of the problem,
charging 15k/sec mean that for every
one second the call last, they charge15 kobo.
When they say express this amount as percentage per minute I become a bit confused.
I am thinking
1 minute= 60 seconds
Expressing the amount as percentage per minute could now mean [math]\frac{15}{60}×100[/math] which is 25%. But am not sure. Could someone please help my understanding?

 

[NotJeffM]

It is not good English. Percentage of what? Percentages are computed relative to something.

Maybe it means “percentage of the value of one naira.” In that case, a minute would cost 900 kobo or 9 naira, which is 900% of the value of one naira. That makes some sense in terms of an arithmetic problem, but it makes no sense whatsoever in terms of how English is actually spoken or written. In the U.S., no one sane ever says “That item costs one thousand eight hundred and twenty-four percent of one dollar.” Native speakers say “That item costs eighteen dollars and twenty-four cents” although mathematically the two locutions mean the exact same thing.

 

[chijioke]

It is not good English. Percentage of what? Percentages are computed relative to something.

Maybe it means “percentage of the value of one naira.” In that case, a minute would cost 900 kobo or 9 naira, which is 900% of the value of one naira. That makes some sense in terms of an arithmetic problem, but it makes no sense whatsoever in terms of how English is actually spoken or written. In the U.S., no one sane ever says “That item costs one thousand eight hundred and twenty-four percent of one dollar.” Native speakers say “That item costs eighteen dollars and twenty-four cents” although mathematically the two locutions mean the exact same thing.

It might interest you to know that this are solutions provided for the problem. Maybe you can make something out of it?

 

[The Highlander]

View attachment 35706
Beginning with the (a) part of the problem,
charging 15k/sec mean that for every
one second the call last, they charge15 kobo.
When they say express this amount as percentage per minute I become a bit confused.
I am thinking
1 minute= 60 seconds
Expressing the amount as percentage per minute could now mean [math]\frac{15}{60}×100[/math] which is 25%. But am not sure. Could someone please help my understanding?

What appears to be happening [for part a) at least] is this ....

The (reduced?) rate of 15 k/sec equates to 900 kobo per minute of service (15 × 60 = 900)

So, for part a), we have:-
To find the "percentage per minute of service": \(\displaystyle \frac{15}{900}\times 100\ \% = \frac{1500}{900} \ \% =\frac{15}{9}\ \% = \LARGE{1}\normalsize{\frac{6}{9}\ \% =}\LARGE{1}\normalsize{\frac{2}{3} \ \%}\)   (QED)

However, for part b), I suspect you may (as usual!) be failing to provide us with all the information required to figure this out!

In part b) 117/30 = 47/30 = 1410/900 and 1410 ÷ 15 = 94.

Does it perhaps say somewhere that someone made a call lasting 94 seconds (or minutes)?
That would be 1 minute & 34 seconds (or 1 hour & 34 minutes)

If there is no further information available then I have no idea how to explain what part b) means. ?‍

So, as ever, please show us a picture of the complete question. ?
(Ideally 'sandwiched' between the questions before and after it.)