MYTUTOR SUBJECT ANSWERS

387 views

How do I make calculations with percentages?

There is a simple way of making calculations with percentages.

Say you want to subtract from a numerical value x,20%. Then multiply it with 80/100.

Say you want to add 20%.Then multiply with 120/100.

Say you want to add 70%. Then multiply with 170/100.

In short,if you want to add x%,then multiply with (100+x)/100. If you want to subtract y% then multiply with (100-y)/100.Note that you can't subtract more than 100%.

Easy,right? :P

Now we will look on a particular tricky question. We have a TV that costs 1000 pounds.Then,the price of TV is reduced with 20%.After some time,the TV is increased with 20%. What is the final price of a TV?

Don't fall into the trap of saying that the final price is the same with the initial one,therefore 1000 punds.

1.) We reduce with 20% : 1000*80/100=800 pounds

2.) We increase the current price with 20%,so: 800*120/100=960 pounds.

So the final price is 960 pounds.

Marco-Iulian G. GCSE Maths tutor, Uni Admissions Test .MAT. tutor, A ...

1 year ago

Answered by Marco-Iulian, a GCSE Maths tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

331 SUBJECT SPECIALISTS

£18 /hr

Sam W.

Degree: Mathematics (Bachelors) - Durham University

Subjects offered: Maths

Maths

“About me Hi! I'm Sam and I'm a second year mathematics student at Durham University.  In terms of my academic background, I achieved an A* at GCSE maths, before going on to study maths and further maths at A level and obtaining a high...”

£18 /hr

Shona S.

Degree: Economics (Bachelors) - Birmingham University

Subjects offered: Maths, Economics+ 1 more

Maths
Economics
Biology

“I am a second year Economics student, studying at University of Birmingham. At school I studied Economics, Maths and Biology for A levels and having enjoyed learning them, so I feel I will be able to enthusiastically teach these subje...”

£18 /hr

Will W.

Degree: Mathematics (Bachelors) - Durham University

Subjects offered: Maths, Physics+ 2 more

Maths
Physics
Further Mathematics
.STEP.

“About Me: I am a Maths and Physics student at Durham University, who has always enjoyed understanding complex concepts in these subjects. I also have a passion for sharing this enjoyment. At my previous school, I ran a Maths Club. Thi...”

About the author

Marco-Iulian G.

Currently unavailable: for regular students

Degree: Mathematics&Computer Science (Masters) - Bristol University

Subjects offered: Maths, Further Mathematics + 2 more

Maths
Further Mathematics
.STEP.
.MAT.

“I'm in my first year at University of Bristol, studying Mathematics and Computer Science MEng. From an early age I started to participate in lots of contests and maths olympiads, and the experience I achieved along the way enriched bo...”

You may also like...

Posts by Marco-Iulian

How can I find x and y?

How do I make calculations with percentages?

How do I solve a quadratic equation?

How do you solve this problem?

Other GCSE Maths questions

How do I find the intersection of a line and a curve?

How do I draw a straight line graph given a y=mx+c equation by the table method?

Every past paper I sit, I miss an A* by a few marks. How do I ensure that I reach that top grade?

What can I say about the roots of a quadratic equation without actually calculating them?

View GCSE Maths tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok