Let original number of bags be x. 146x+128=143(x+1) 3x=15 x=5 So answer is 6.

Thanks but sorry,can you explain with another method?i don't understand it.

Why there is 3 bags for 146?

The drawing is to illustrate a few bags of 146 (as we don't know initially how many there are). Hence u see I put ...... behind that 3 bags.

Sorry i cannot read that it the colour is so light

Hi Yeo See Yeong Its ok...i manage to understand it...Thank you!

An idea of average is to distribute/redistribute the nails in order to get an equal amount in every bag. When a bag with 128 nails is added, we know that it needs additional nails to get 143 nails. How many additional nails does the last bag need? It needs another 15 nails (143-128=15). To get the 15 nails, we have to take 3 from the other bags that had 146 nails at first so that each bag can have 143 nails (the meaning of average). Next question: to take 3 nails from each bag, how many bags can give us 15 nails? Answer is 5 bags (3 nails each from 5 bags gives us the 15 nails). So we now know that there were 5 bags at first. Including the last bag, we now have 6 bags.

Thank you for your explanation tooVei Li Soo ... i manage to understand on your explanation and Yeo See Yeong ...appreciate it very much. Btw this is my mum's fb 😊

1/2 x 20 cm x 12 cm = 120 square cm

Xavier Sng it is 120 cm∧2, not 120∧2 cm

Rye Tan.....erm, you are sadly mistaken. https://www.mathsisfun.com/definitions/square-centimeter.html

What I mean is, you should show that the "square" belongs to the "cm" , not "120". I misread and misunderstood your comment.

Use "∧" next time instead.

Is okay, a lot of folks don't understand what a square cm is. Regards

Xavier Sng you are a student? or a teacher? O.o

Neither.

Parent?

Nope.

teacher include tutor ah.....

And "student" is not restricted to Primary school students.

Not in my books I am afraid.

Hi Xavier, I dun understand your answer 1/2 x 20cm x 12 cm. Can explain how you get the answer. Thanks.

Hello Shaw. The area of a triangle can be determined by the product of 1/2, base length and the perpendicular height. The base length is CB, which is 20cm. The perpendicular height is DC, which is 12 cm. AB, which is not the perpendicular height is just the red herring to mislead the student.

This question is testing the student's ability to identify the height of the triangle.

Thanks Xavier

The pleasure is mine. Regards

1/2 x 20 x 12 120

Thank you.

Hope it helps.

Thank you both for d quick replied👍

I can't get it why A+C = 1/2 of the rect :3 can someone explain

Thank you, Xavier.

My pleasure, Lincoln. Regards

We are assuming EF to be the mid point of the rectangle?

Hola, Joshua. Triangle A and Triangle C share the same base length. The sum of their perpendicular heights is equal to the width of the rectangle. That is why the sum of the areas of Triangle A and Triangle C is half the area of the rectangle.

Ohh nice :) thanks now that made sense

Glad you can see it! Regards

Ok, get it too. Thanks.