MYTUTOR SUBJECT ANSWERS

739 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 ...

2 years ago

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


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

630 SUBJECT SPECIALISTS

PremiumGeorge B. GCSE Maths tutor, A Level Maths tutor, A Level Further Math...
£24 /hr

George B.

Degree: Mathematics (Masters) - Warwick University

Subjects offered:Maths, Further Mathematics + 1 more

Maths
Further Mathematics
.STEP.

“Premium tutor. First class graduate with teaching experience from a top Russell Group university. I deliver fun and relaxed lessons which achieve results!”

£18 /hr

Mihai P.

Degree: Natural Sciences (Bachelors) - Cambridge University

Subjects offered:Maths, Chemistry+ 2 more

Maths
Chemistry
Biology
-Medical School Preparation-

“I would like to share my passion for science and help you discover the key patterns which govern our world.”

£24 /hr

Prina S.

Degree: Environmental Geoscience (Masters) - Bristol University

Subjects offered:Maths, Physics+ 2 more

Maths
Physics
Geography
Biology

“Hello there! My name is Prina and I love studying and tutoring maths and science. Check out my profile for how I teach and previous students' feedback!”

About the author

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

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 know whether to add or minus in Pythagoras's theorem?

Find the possible values of x for x^2 = 36-5x.

Solve 5x – 2 > 3x + 11

simultaneous equations - 2x + y = 7 and 3x -y = 8

View GCSE Maths tutors

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

mtw:mercury1:status:ok