Wow Xavier Sng! Your eyesight super good! I couldn't even figure out the question! 👍

Ha! You flatter me, Isabella. I needed my reading glasses, had the picture enlarged till I can see the pixelation, and I had brought my nose so close to the touch screen of my lappie so many times that it kept going to other windows. In all honesty, I just assumed that the height of the tank is 160cm. Regardless of whether that piece of information is correct or not, the method is fine.

my boy ans a) 2min 30 sec b) 10 cm

Thanks,can you explain why

@Joyce Yeo

Why 4 cm increase per min?

Don't understand too..

1.2litre divide by 15 cm and 20 cm = 4 cm.

Thats for a per minute

1st step is to find the rate of water flowing/draining per min

Thanks guys: Joyce Yeo, Rye Tan,& Xavier Sng Now,i am sure and manage to solve the question...i appreciate it very much☺

Thank you Angel. Regards

Rye Tan, could you explain the second step on the second photo, I'm lost?

What he meant was that water level in Tank A, which is the product of the rate of 4cm rising per minute and the time taken is equal to the water level in Tank B when the product of the rate of 2 cm falling per minute and the time taken is subtracted from the original water level of 15cm.

Noted. Thanks Xavier Tan. I'm just trying to link this to the question I ask last week, where you helped to solve.

It is then paraphrased as the sum of the rate of 2cm change in water level per min and the rate of 4cm change in water level per min multiplied by the time taken being equal to 15 cm of water level.

Happy to help Sedrickm. Regards

https://www.facebook.com/photo.php?fbid=10153186955204353&set=gm.500702996753028&type=1&theater

Area of triangle AED = 196 cm^2 AD^2 = 4 x 196 cm^2 AD^2 = 784 cm^2 AD = 28cm Diameter of smaller circle = 28cm /(2+5) x 2 = 8cm Diameter of bigger circle = 28cm - 8cm = 20cm Area of triangle BCF = 0.5 x (Radius of smaller circle + Radius of larger circle) x (Radius of larger circle) = 0.5 x 14cm x 10cm = 70 cm^2