Active discussions

Meet the Other Phone. A phone that grows with your child.

Meet the Other Phone.
A phone that grows with your child.

Buy now

Please or to access all these features

Talk
Chat

Join the discussion and chat with other Mumsnetters about everyday life, relationships and parenting.

Original poster

Maths question

15 replies

QueenMabs · 12/03/2023 07:37

I have a £25 voucher

The shops is offering 20% discount

What original value of goods can I buy for exactly £25?

I tried 25x 1.2 = 30

But

30x 0.8 = 24

How do I work this out?

OP posts:
howaboutchocolate · 12/03/2023 07:41

You need £25 to be 80% of the original price, so 25/0.8 which is 31.25.

Needtobuildabridge · 12/03/2023 07:42

The answer is £31.25.

The percentage of the original number is 100% - 20% = 80%.

So 80% of X is 25.
This means that 1% of X= 25 ÷ 80 = 0.3125

So 100% of X = 0.3125 x 100 = 31.25

So the original number is 31.25.

Answer: A 20% decrease from X = 31.25 =

meltingmyhead · 12/03/2023 07:42

£31.25 I think, 20% takes £6.25 off

Interested in this thread?

Then you might like threads about this subject:

General education
Original poster
QueenMabs · 12/03/2023 07:43

Thank you @howaboutchocolate beautifully explained. Of course 🤦‍♀️

I'm normally able to reason this out through logic but today this failed me!

OP posts:
newschoolneeded · 12/03/2023 07:43

X * 0.8 = 25

X = 25/0.8

X = 31.25

jimjamy · 12/03/2023 07:44

80% of price = £25

0.8 of price = 25

price = 25/0.8

newschoolneeded · 12/03/2023 07:44

I was too slow!

TeenDivided · 12/03/2023 07:48

How nice to have a maths thread full of correct answers.

I suggest MN closes the thread now! Grin

Original poster
QueenMabs · 12/03/2023 09:12

@TeenDivided to be fair I was being massively thick.

Maybe you can indulge me with what to buy from m and s!

OP posts:
TeenDivided · 12/03/2023 09:36

QueenMabs · 12/03/2023 09:12

@TeenDivided to be fair I was being massively thick.

Maybe you can indulge me with what to buy from m and s!

You weren't being massively thick. There was a similar thread the other day with quite a few incorrect calculations.

M&S? jeans or knickers?

cakeorwine · 12/03/2023 10:28

This is a good example that can be done with a picture

80% of a number is £25

What is the number?

You can draw a rectangle with 10 parts to it - and you can then shade in 8 of them (each part is 10%). Then work out 1 part. And then you can work out the original number.

RaelImperialAerosolKid · 12/03/2023 11:16

You were in no way being massively thick. You tried the calculation - realised that you were doing something wrong - asked for help - took time to read the answers and understood what mistake you had made.

Seems pretty intelligent to me.

Original poster
QueenMabs · 12/03/2023 12:42

If I'd worked out that it was 80% of the original then I would have done (25/80)*100

I think it's knickers but that is a lot of knickers

OP posts:
CatOnTheChair · 12/03/2023 13:07

Knickers, I like some of their teeshirts. Jeans.
Top up the amount with packets of percy pigs and mini Colin's to get as close to 31.25 as you can!

LOTS of people get confused converting reduced amounts to full price.

Original poster
QueenMabs · 12/03/2023 13:52

That is an amazing idea. I can spent the discount on Colins and Percys!

OP posts:
New posts on this thread. Refresh page