I second that

Cut and crop the picture in EDIT MODE .. Thnx

I like your equations. I can see in the third equation you subtracted 3.42 - 2.25 to get 1.17. If you do the same thing with the other two parts of the equation you would get box - box = 0 and 48 plastic cups - 30 plastic cups = 18 plastic cups. So 18 plastic cups = 1.17 kg and one plastic cup = 0.065 kg. Using the first equation, box + 30 x 0.065 = 2.25, box + 1.95 = 2.25, so the box = 0.3 kg.

1.17kg is the weight of 18plastic cups.. 30Cups= 1.17 ÷ 18 x 30= 1.95kg Box +30cups(1.95)=2.25 Box= 2.25-1.95=0.3kg(answer)

Oh now I get it. Thanks all!

not really sure whether my working is correct. do inform me the correct answer if you have the solution, thanks!

Shi Hui Lhu your 11:3:11 was wrong.. Should be 1:3:11.....

opps sorry, didn't see it clearly

Yeo See Yeong,thanks my daughter she find total already but she very confused how to do next step. :)

Yeo See Yeong, may I ask you whether my daughter did the correct steps but she also has the correct answer.

She is absolutely correct.

Wah...thanks for help &comments :)

OR: she receive 60 but give out 70, so net outgoing is 10. Hence she can just use 210+10 to get 220.

Just that the bar for C needs to reflect 11u and not 11u-70.

Ok, Yeo See Yeong :)

Thank you so much.

You are most certainly welcome. Regards

Pattern 1: 1 layer Pattern 2: 2 layers Pattern 3: 3 layers. Hence, pattern number ＝ number of layers.

Layer 1: 1 cube Layer 2: 4 cubes Layer 3: 9 cubes. Hence, number of cubes in any layer ＝ layer number × layer number ＝(layer number)∧2

Hence, Number of cubes in Pattern 4 ＝ 1+4+9+16 ＝ 30

Volume of 1 cube ＝ 27 cm∧3 Volume of Pattern 4 ＝ 30×27cm∧3 ＝810 cm∧3

1x1+2x2+3x3 +4x4=30 for 4. Next is plus 5^2. Then 55 . Next plus 6^2. 91

(c) 1 + 4 + 9 + 16 + 25 + 36 + 49 = 140 Pattern 7 contains 140 cubes. There is a formula to add up square numbers, but that is taught at A levels and the formula is very much above the head of primary school students.

thanks everyone for the solution.