Thanks Xavier, can I ask why 60+60+40? Thanks

You are welcome. The question asks that the water height in tank P be twice that of tank Q. So to make it easy to calculate we divide the total volume of water over the combined base areas of TWO tank P's and one tank Q. The result will be the water height in tank Q. Multiply that by two and we get the answer.

Thanks, understood le, thanks again

Please don't mention it. So you will know what to do if the water height in tank P is to be four times of tank Q?

Yes, thanks

Excellent!

Hi, I don understand how to get 10x - 7x/ 700? Thanks

For part b, I think the answer is 2800 copies as the question mentioned that both machines printed same number of copies.

Speed difference is 6. So, x/70 - x/100 = 6. Simplify that will have 10x-70 / 700 = 6

Jason, u shd be right. I am assuming the faster machine continues to print till 1pm.

Thanks See Yeong, for primary school kids, I believe their understanding of algebra is not yet sufficient to apply such equation; reason why they could base on understanding the number of more copies printed by the faster machine over the entire 70 mins is printed by the slower machine when the faster machine finishes printing (ie. 420 copies in 30 mins)

0_0 This is PSLE booklet

1/10 + 1/12 + 1/15 = 6/60 + 5/60 + 4/60 = 15/60 = 1/4

Thxs. My boy did this too but my boy say teacher say wrong. So i scratching my head

You are welcome. Please do check with the teacher why your son's solution was not accepted. If your son's solution yields the same answer but is different in presentation, please show it to me. Thank you.

Xavier Sng, i outside now but he wrote exactly like yrs. Maybe he is confused too as it seemed this is his 2nd attempt. 1st working def wrong. I will check w teacher.

There another part of the qn is how many hrs will the 3 workers complete the job together?

Since they complete 1/4 of the job in an hour, the entire job will take 4 hours if they all work together.

How do you get 4 hours if they work together?

Oic! Thxs for the answer. Gek Poh, for 4 hrs they will complete 1 job. Maybe u draw the model or pie u will start to see it.

1 job is 4/4

(a) Shaded area = 1/2 × Pi × 20^2 + (1/4 ×Pi × 40^2 - 20^2) = 1484.96 square cm corrected to 2 decimal places (b) Perimeter = Pi × 40 + 1/4 × Pi × 80 = Pi × 60 = 188.50 cm corrected to 2 decimal places

thank u so much

Please don't mention it. Regards

(a) 4.45 cm × 5 = 22.25 cm (b) (216 ÷ 1.35) + 1 = 161

thank u thank u

Please don't mention it. Happy to assist.