Daily Mail Mindbender 18 Auggust 2023

[Magsiksnys]

Martin bought some ribbon but when he got home he had too much and reakised hmust hab=ve mixed up hte feet and inchhes. He had 12% more than needed. How much has he got left.

The answer is 4' 7'' but how do we get the answer mathematically without trial and error

Tia

[Magsiksnys]

Typo 125% more ribbon. Sorry

[bobbinwales]

if he wanted x feet + y inches total lentgth he wanted = 12x +y inches.
What he got was x +12y inches which is 2.25 (225% of what he wanted)
Take it from there

[bobbinwales]

I think some trial and error is still needed though

[petland]

4' 7" represents 125% of his purchase so in inches he should have bought
55/125x100= 44" or 3' 8"
But he transposed the figures and bought 8' 3" or 99"
what he bought minus what he used gives the amount left over so
99 - 44 = 55 (4' 7")

[bobbinwales]

It doesn't tell us in the question tho that the answer is 4ft 7⁷

[Tilly2]

I'd just save the extra ribbon.

[petland]

Further to Bobbinwales posting yesterday to complete the calculation:-
12y + x = 2.25 x (12x + y)
multiply by 100 to eliminate the decimal point
1200y + 100x = 225 x (12x + y)
1200y + 100x = 2700x + 225y
975y = 2600x
The only sensible value for x is 3 and y is 8
So he wanted 3' 8" of ribbon but purchased 8' 3" a difference of 4' 7"

[bobbinwales]

yes 2600/975 simplifys to 104/39 = 8/3.... thats how I done it

[Magsiksnys]

thank you