Question

LAST HOMEWORK QUESTION PLEASE

On the production line, it takes John 2 minutes less time than Mark to assemble a watch. Working together they can assemble 5 watches in 12 minutes. How long does it take John to assemble a watch working alone?

My idea was:

12 12
--- + ---- = 12x(x-2)
x-2 x

12x + 12(x-2) = 12x^2 - 24

12x+ 12x - 24 = 12x^2 - 24
24x - 24 = 12x^2-24
0 = 12x^2 + 48 - 24x
0 = 12(x^2 -2x + 4)

I got lost here since I can't factor it:

Any ideas? Thanks!

Answer 1

mm... lemme see it :)

Answer 2

oh wow dats complicated

Answer 3

So if it takes John 2 less minutes, the final difference for 5 watches is 10 minutes. Because it takes Mark takes 5 min for 12, and John does 2 min less. Lmk if you don't understand why! So basically you do 12 - 10 and you get that it is 5 watches in 2 minutes. So from there, you divide 2 minutes by 5, and you get the answer!