Please help me!

Alex is 20% less efficient than Brian. If Brian can complete a work in 20 days, how long will Alex take to complete the same work? I tried solving it the following ways: ( but my teacher said I was wrong and he wouldnt even tell the correct answer till a week and this is bugging me!!!)

Alex= Brian+20%of Brian

   =20+20% of 20

   =20+4

   =24 days

Please tell me the correct answer and also why my way is wrong.

#Algebra

Easy Math Editor

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Comments

I'm only giving a hint: How would you do this if A was 50% less efficient? It should take twice as long, right? But if you use your method it would only take 30 days. Figure out a method where the answer to my question is 40 days, then you can fix the answer to your teacher's question.

Jeremy Galvagni - 2 years, 11 months ago

Wow thank you. No wonder I wouldnt have known that. My teacher explained it to me. I learnt a new thing. 15 is 25% more than 12 but 12 is not 25% less than 15. SO, the correct answer is 25. Maths is always interesting!!!

Funny Moments - 2 years, 11 months ago

I too think that the correct answer is $24$

Ram Mohith - 2 years, 11 months ago

It's actually 25.

Jeremy Galvagni - 2 years, 11 months ago

What the heck? 20% of Brian?

Annie Li - 2 years, 11 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$