MYTUTOR SUBJECT ANSWERS

324 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 ...

12 months ago

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

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

333 SUBJECT SPECIALISTS

£18 /hr

Jed M.

Degree: Natural Sciences (Bachelors) - Exeter University

Subjects offered: Maths, Chemistry+ 1 more

Maths
Chemistry
Biology

“Hi! I'm a second year Natural Science student at the University of Exeter. I love all things science, and enjoy sharing what I know about it with others. For my GCSEs and A Levels, I found worked examples and practice questions are ke...”

£20 /hr

Vinayak N.

Degree: medicine (Bachelors) - Nottingham University

Subjects offered: Maths, Chemistry+ 2 more

Maths
Chemistry
Biology
-Medical School Preparation-

“ABOUT ME AND MY TEACHING STYLE     I am a final year medical student at Nottingham and I like to take a friendly relaxed approach to both being a student and a teacher. I am easy going and very passionate about both teaching and scien...”

£18 /hr

Hamid S.

Degree: Mechanical Engineering (Masters) - Cardiff University

Subjects offered: Maths, Physics+ 1 more

Maths
Physics
Chemistry

“About Me: I am a first year Mechanical Engineering student at Cardiff University. Though I’ve only just began my course, I’ve had a major interest in engineering and science since I was very young, always being hands on and more recen...”

About the author

£18 /hr

Marco-Iulian G.

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

Test

Factorise 4xy-6xz

Solve the simultaneous equations: 4x + y = 25, x - 3y = 16

Can you explain the formula method for solving quadratic equations?

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