Thanks Raymond! You are the boss! 😃

BTW, Lukas Lee's solution has some tiny bit of error. It's a trapezium n the formula he gave at the bottom of the page is for area of trapezium

Oh yeah, I'm sorry for the booboo.

Also, question stated that value of pi should be 3.142, not 3.14. But the method is of cos correct

Thank you Ariel & Lukas

Perimeter can?

I'm really bad in Maths

Just add up the "outside" lengths. Only missing lengths are the arc lengths of the semi circles.

2 semicircles = circumference of circle = (pi) x diameter = 2 (pi) x radius

Step 1: find the amount used for Watches and Clock. Amount used to buy clock = $(5190-$2310)/2 = $1440

Hence amount used to buy Watches = $3750

First find the cost of watches and clocks. A simple model with "more than less than" should suffice. $5190 - $2310 = $2880 $2880 / 2 = $1440 (cost of clocks) $1440 + $2310 = $3750 (watches) So for every 4units of clocks he buys 5units of watches. His 5units of watches in total cost him $3750. So per unit of watch is $750. His 4units of watches cost him $1440. So per unit is $360. If clocks cost as must as watch the unit price should be the same. But they are $39 less per piece. So $750 - $360 = $390 So each unit of clock and watch has a difference of $390 this means each unit of clock or watch is made up of 10 pieces. So there are 40 clocks and 50 watches.

Haha I am too slow to type. Eugene is much faster :).

Work backwards with calculator to check. 3750 / 50 = 75 (per watch) 1440 / 40 = 36 (per clock) 75 - 36 = 39 (price diff)

Apologies Vincent! We should petition FB to allow us to draw models! Ahahaha

Haha, no worries Eugene. Yes draw models on FB would b great :)

Very clear explanation Eugene Ng Ming Teck....

thank you all for helping me. thank you Pauline Vong Nyit Li, Vincent Ong and Eugene Ng Ming Teck.

22cm x 4 = 88cm

Same total length for all 4 sides. Ok?

Ok thks!

It's 88 cm.