MYTUTOR SUBJECT ANSWERS

744 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

531 SUBJECT SPECIALISTS

£20 /hr

Naomi S.

Degree: Medicine (Bachelors) - Trinity College Dublin University

Subjects offered:Maths, Music+ 4 more

Maths
Music
Human Biology
Chemistry
-Medical School Preparation-

“*Available to teach exam revision sessions immediately.* I'm a medical student at Trinity College Dublin. ”

£18 /hr

Eleanor J.

Degree: Natural Sciences in Maths and Physics (Masters) - Durham University

Subjects offered:Maths, Physics+ 1 more

Maths
Physics
Further Mathematics

“Study Maths and Physics at Durham Previous tutoring experience Enjoy helping students improve and enjoy the subjects Adaptable to different academic needs”

£20 /hr

Madeleine N.

Degree: Natural Sciences (Masters) - Durham University

Subjects offered:Maths, Spanish+ 2 more

Maths
Spanish
Physics
Further Mathematics

“Enthusiastic student, studying Maths and Physics at Durham university: keen to work hard with students to improve their results.”

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

How do I expand (3x + 6)(x + 2) ?

Solve these simultaneous questions: 2y+x =8 and y-2x = -1.

Solve the equation (2x+3)/(x-4)-(2x-8)/(2x+1)=1 and give the answer to 2 decimal places

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