increase percentage problem

• Jul 22nd 2009, 04:57 PM
shaz09
increase percentage problem
Hi guys

I am having problems with this example, not sure how I would go about this without using a calculator.

All 300 Year 11 pupils in a school took GCSE English. The number of pupils gaining grade C
or above increased from 85% in the mock exam to 93% in the actual exam.
How many more pupils gained grade C or above in the actual exam than in the mock exam?

Thank you
• Jul 22nd 2009, 05:43 PM
HallsofIvy
Quote:

Originally Posted by shaz09
Hi guys

I am having problems with this example, not sure how I would go about this without using a calculator.

All 300 Year 11 pupils in a school took GCSE English. The number of pupils gaining grade C
or above increased from 85% in the mock exam to 93% in the actual exam.
How many more pupils gained grade C or above in the actual exam than in the mock exam?

Thank you

What is 85% of 300? What is 93% of 300? What is the difference between those two numbers?
• Jul 22nd 2009, 05:47 PM
shaz09
Not sure what you mean

but do you mean turn to fraction so 85% would become 17/20

? how would i do this to 93?(Thinking)
• Jul 22nd 2009, 05:54 PM
Wilmer
Quote:

Originally Posted by shaz09
All 300 Year 11 pupils in a school took GCSE English. The number of pupils gaining grade C
or above increased from 85% in the mock exam to 93% in the actual exam.
How many more pupils gained grade C or above in the actual exam than in the mock exam?

The increase: 93 - 85 = 8%
1% of 300 = 3 ; so 8% = 24 ; follow that?
• Jul 22nd 2009, 05:55 PM
shaz09
thank you, I never knew that before (Surprised)
• Jul 23rd 2009, 05:05 AM
HallsofIvy
Are you really saying you do not know how to find a percentage of a number?

I asked "what is 85% of 300". That is: 0.85*300= 255.

I asked "what is 93% of 300". That is: 0.93*300= 279

Since 255 students got a "C" or better the first time and 279 got a "C" or better the second time, they improved by 279-255= 24 students.

Of course, Wilmer's method works too. But I think this is a little more direct.
• Jul 23rd 2009, 05:35 AM
Wilmer
well
Hard to tell, Mr Hall.
He seems to be trying to find the easiest way to solve without calculator.
So I guess he'll get as many "answers" as there is "responders"!
• Jul 23rd 2009, 10:03 AM
shaz09
Hi Hall

I am revising for a exam which I have to do as part of my course, you can take as many times. I am not trying to do a home work or anything like that, the exam has 16 questions and they are all mental articmatic questions. you have 54 secs to complete the question.

Without using a calculator, I find this hard however i am revising and trying to find the best methods to answer the questions quickly.

Thank you
• Aug 3rd 2009, 07:29 PM
shaz09
Percentage problems
Hi guys

Having problems with these types of questions

for example say in a class of 30, 40% achieved half marks or above. How many people have gained less then half marks

Okey so we have 40% and 30 students

60% have gained less then half marks

we can make this 3/5 and then divide 30 by 5 to make it 6 and then * 6 by 3

Is this right?

$\text{60}\% \;\text{of}\; 30 = \frac{3}{5} \cdot 30 = 18$