MYTUTOR SUBJECT ANSWERS

596 views

how do you find the original price of something that has been changed by a percentage decrease

Lets say something has been decreased in price by 20% and is now £40. The tempting thing to do here is to find 20% of 40 and add it back on, but this is not okay! The reason we can't do this is that 20% of 40 is different to 20% of the original, bigger number. Instead, think of our original number as 100%. We took away 20% so now we have 80% left, how can we get back? well, if we divide 80% by 4 we get 20%, then multiply it by 5 we get 100%! Do the same to the £40, which is our 80%, and you will get back to the original. I like to draw a grid

80% = £40

divide by 4

20% = £10

multiply by five

100% = £50

Steven K. GCSE Maths tutor, A Level Maths tutor, Mentoring -Personal ...

2 years ago

Answered by Steven, a GCSE Maths tutor with MyTutor


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

507 SUBJECT SPECIALISTS

PremiumJacan C. A Level Maths tutor, A Level Physics tutor, GCSE Physics tut...
£36 /hr

Jacan C.

Degree: Theoretical Physics (Masters) - York University

Subjects offered:Maths, Science+ 3 more

Maths
Science
Physics
Further Mathematics
Chemistry

“Helping the striving and the struggling with caring, friendly and structured tuition. With 200+ hours of experience, offering Physics, Maths and Chemistry.”

£18 /hr

Matilda C.

Degree: Medicine (Bachelors) - Edinburgh University

Subjects offered:Maths, Science+ 4 more

Maths
Science
Chemistry
Biology
.UKCAT.
-Medical School Preparation-

“Hi, my name's Matilda and I'm a third year, cricket-loving medical student at the University of Edinburgh. I have a genuine love of helping other people and doing my very best of have a positive impact on their lives; this is at the c...”

MyTutor guarantee

£18 /hr

Elliot D.

Degree: Mathematics (Bachelors) - St. Andrews University

Subjects offered:Maths, Physics

Maths
Physics

“Hi, I'm a 2nd year Computer Science student at St Andrews University. I mainly teach Maths at both GCSE and A-level.”

About the author

Steven K. GCSE Maths tutor, A Level Maths tutor, Mentoring -Personal ...

Steven K.

Currently unavailable: for regular students

Degree: Material Science (Masters) - Oxford, The Queen's College University

Subjects offered:Maths, -Personal Statements-

Maths
-Personal Statements-

“I started tutoring through my father who is a maths teacher, as he would pass on requests for lessons to me. Through my A levels I tutored GCSE maths, and began to also teach physics, chemistry and biology, the other subjects i was st...”

You may also like...

Posts by Steven

how do you find the original price of something that has been changed by a percentage decrease

What's the difference between ionic and covalent bonds?

Why do we need active transport if we have Diffusion?

Other GCSE Maths questions

Find the equation of the straight line which passes through the point (0, 3) and is perpendicular to the straight line with equation y = 2x.

Complete Question won't fit here. Please see Explanation. Thanks.

Expand and simplify (x+12)(x-3)

3x^2 + 7x - 13 = 0. What is x?

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