mje_wrx

iTrader: (6)

Can someone work this out with solutions.

its from a mechanical aptitude practice test.

i can work out 17 and 19

but 18 and 20 just isn't happening.

I know for most it maybe easy, but i just cant get it. tried for hours.



iv got the answers but not the math behind it all.

Thanks Matthew

Terminator X

iTrader: (7)

I'll be the first ... "maths"!

TX.

mje_wrx

iTrader: (6)

depends on if your American or not

no solution to the MATHS from you, so il assume you cant work it out

Terminator X

iTrader: (7)

Lol, I'll try 18 for you:

70 x 65 = area before hole cut out = 4550cm2 = 100% of area.

pi x r squared = area of circle = 22/7 x 30 squared = 2829cm2.

30 x 30 = area of square = 900cm2.

Wasted area is 4550 - 2829 + 900 = 2621cm2.

2621 / 4550 = 58%. After all that there is no 58% answer

TX.

subaruturbo_18

Why is it 70 X 65? i don't know what a steel coil is/ if it's 70 width and has no height, i am guessing you need to know what the coil's dimensions are?

I would have done the maths the same way as you would though.

vindaloo

17:

Size of component including centre = pi*30*30 = 2827.43cm^2

Size of centre discard = 30*30 = 900cm^2

Remaining shape = 1927.43

18:
Raw materials per component:

70 x (60+2.5) Width of sheet times component size plus 25mm.

= 4375 cm^2

Total wastage = 4375 - 2827.43 + 900 = 2447.57

Percentage wastage = (2447.57/4375) * 100 = 55.9%

19:

25 metres = 2500cm so

2500/62.5 = 40

20:
Cost of component before scrap = $200/40 = $5
Scrap value = $100 * 0.559 = $55.9
Scrap reclaimed per component = $55.9/40 = 1.3975

Component cost = $3.6025

----------------------------

I'm sure 20 could be done a little more elegantly and avoid doing the divide by 40 twice.....

J.

vindaloo

I think it's 25mm either side of each component (2.5cm + 60cm + 2.5cm). You only need to count it once though IMO.

Just as well I tried to understand his answer though. I'd not seen the CM and MM. I started trying to make it work with 85CM!

J.

mje_wrx

iTrader: (6)

thanks vindaloo, thats all correct to answers.

thanks for workings out, couldn't believe how close i was to the answers.

didn't take 1.4 fro 5 on question 20. Im a dumb *** lol

and -900 not plus on question 18.

Thanks for that, done my head in all day.

aptitude test practice for a job.

last time i done maths was 2001 leaving school

wayne9t9

10/10 v. good

Terminator X

iTrader: (7)

70cm wide as you say. 2.5cm gap between each component, 60cm diameter on circle so:

60 + 2.5 + 2.5 = 65cm.

TX.

Edit - Vindaloo done me on the 2.5 + 2.5, as he says you only need to use one 2.5

2nd edit - my job revolves around numbers fpmsl

scubbay

iTrader: (61)

Terminator you only need 1.25 either side of each component, i.e. 1.25 on the left of one component plus 1.25 on the right of the other means a 2.5 gap, what your doing is leaving a gap of 5 between components.

speedking

20. Cost of material per component = $200 / 40 = $5.
Waste = 56% but half that recovered from sale of scrap.
So recovery from sale of waste = 28%.
Cost of component = $5 x 72% = $3.60. (Material cost only )

chiroman

iTrader: (1)

20.
total cost $200 - $200x55.91/2 x100

= $200 - 55.91

= $144.09

unit cost = $144.09/40 = $3.6

wayne9t9

Mixed units? $$$$$ and cm`s, everyone knows yanks can`t do metric