11+ maths question

[united4ever]

If there are 300 pupils at a school and 99 are boys what percentage are girls?

So this can be worked out by small number divide by big number and multiply by 100.

Trouble is my daughter cannot easily work out 99÷300.

Is there an easier way for this type if question?

In this case it's nearly a 100 so you can almost guess it is 33% boys and 67÷ girls but I want to know the easiest way so we can apply to all these questions.

Thanks!

99÷300=0.33
0.33x100=33

I think!

You can apply that formula to similar questions

I would say get her to write it as a fraction and manipulate it until it's out of 100.

Eg. This is 201/300 = 67/100 so 67%

Write as fractions:

99/300 = 33/100

By year 6 they should know that to convert a fraction to a percentage they make the fraction over 100, then the top number is the percentage (33%), but then of course it’s asking for girls not boys, so 67%.

No rounding/guessing necessary, it’s exactly 67% as the answer.

Thanks. The converting to fraction method makes sense.

One more if you can?

If a car travels 260 km from Leeds to newcastle at 50kph and leaves at 1pm. What time does it arrive?

What percentage are girls?

201 girls our of 300 kids
(201:300)X100
67%

By converting to a fraction 99/300, she should hopefully see that they can both be divided by 3, so that becomes 33/100, which is then a simple percentage.

If a car travels 260 km from Leeds to newcastle at 50kph and leaves at 1pm. What time does it arrive?

6.20pm

260/50 = 5 r 10.
10km will take 1/5 hour.
1/5 hour is 12 minutes.

260km will take 5 hrs 12 minutes, so the journey ends at 6:12pm.

@united4ever

Thanks. The converting to fraction method makes sense.

One more if you can?

If a car travels 260 km from Leeds to newcastle at 50kph and leaves at 1pm. What time does it arrive?

Tell him to think about some questions in real-life terms - not necessarily applying a formula each time, if he can’t think of one. And don’t be shy to draw things out.

So, 50km in one hour, 100km in two hours etc, all the way to 250km in 5 hours.

Then, the 10km leftover:

If you travel 50km in 60 mins, divide them both by 5, to find out that 10km will take 12 minutes. So, 6:12pm

1/5 hour is 12 minutes. Yes!!

You/he need to think logically about what is being asked and what info you have. Just asking MN for the answers isn't going to help him. So what does 50 km/h actually mean?

Thanks again. Yes 10km will take 1/5 of an hour was the key. Thanks all!

OMG, that question has no answer, did they not even consider the non-binary when they set that???

@NoFanJoe

OMG, that question has no answer, did they not even consider the non-binary when they set that???

@NoFanJoe There would need to be a LOT of updating to SATs/GCSE/maths textbook questions, particularly on probability, if we suddenly decide sex isn’t binary 😂

What age is the child, because both of those questions should be quite straightforward for a year 6 child who is working at expected standard.

@DietrichandDiMaggio

What age is the child, because both of those questions should be quite straightforward for a year 6 child who is working at expected standard.

She is 9 and year 5. This type of wordy maths question is definitely her weakness. Sometimes hard to work out what calculation to do especially at speed also.