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Maths question

Please refer to the attachment.

Does anyone know any quick methods to do this question?
I had to fill in the entire table to get the answer on my 2nd attempt. But this took really long and I had to do a lot of trial and error.
(edited 2 years ago)
Practice test B7 took really long.png242.7KB
Working out.jpg50.2KB
Original post by As.1997
Please refer to the attachment.

Does anyone know any quick methods to do this question?
I had to fill in the entire table to get the answer on my 2nd attempt. But this took really long and I had to do a lot of trial and error.

Hey! :smile:

This problem is actually quite fun to deduce and filling the table is unnecessary if your work is organized. This speeds up considerably the process!

First, let's set up our variables.

Opening weight = OW
Closing weight = CW
Blackcurrant = b
Strawberry = s
Coffee = co
Vanilla = v
Chocolate = ch

The first thing they tell you is that the consumption of blackcurrant (b) and strawberry (s) was the same.
OW(b) - CW(b) = OW(s) - CW(s)
So from this you immediately know that the subtraction between the opening weight and closing weight is the same.

The closing weight of the coffee (co) is the lightest, so you can associate it with the 8kg immediately.
CW(co) = 8kg

The opening weight of strawberry is also heavier than blackcurrant but lighter than chocolate (ch)
OW(ch) > OW(s) > OW(b)
You know now that the opening weight of chocolate is not the lightest. Therefore you can immediately deduce that 12kg is not the opening weight as it is the lightest of the batch.

Now, half of the opening weight of vanilla was consumed that day, and the consumption of chocolate was the second highest.
When you compare the opening weights and the closing weights, you see that none of them are half of each other except the 14kg closing weight and the 28 kg opening weight (14*2=28). From this you can easily deduce that the CW(v) = 14kg

And now you're left with finding trivially that the total consumption of blackcurrant (b) and strawberry (s) is 2 (15-13 =2 and 17-15 = 2) which eliminates both because you know they are the same.

Which only leaves 21kg as opening weight and 16kg as closing weight.

21-16 = 5kg.

Hope that helps!! It's another way of doing the table, but also writing down the appropriate equations to build your ability to solve them if the need ever arises.

Feel free to reach out with more questions if you need so :smile:

J - Studeo

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