Maths homework help please.......y7.

[Ruprekt]

Pirate Pete found rubies in a tin.

He gave 1/3 rubies to his mate.....

And 1/5 to his bosun......

He kept the other 28 to himself....

How many rubies did the bosun get?

321.......go!!

The total amount in the tin has to be divisible by 5 and 3, so take numbers that are divisible by 5 and 3 and see if the sum works out. It doesn't work for 15, 30, or 45. If you try it with 60, you get this:

60 rubies in the tin.

Mate gets a third, so 20.

Bosun gets a fifth, so 12.

Pirate gets 28.

Add these three numbers together, 20 + 12 + 28 = 60. That sum works, so the bosun gets 12.

The mate received 5/15ths
The bosun received 3/15ths
Pete received 7/15ths

7/15ths = 28
1/15 = 4

This the bosun received 3x4 = 12

I got 12 as well but did it different.
Worked out a common denominator which is 15. Then converted each fraction. So fractions are 1/3= 5/15 And 1/5= 3/15 so add them together for 8/15.
So the 28 represents the rest- 7/15 so 28 divided by 7 x 15 is the total which is 60.
Then go back to you original fraction. 1/5 of 60 is 12.

Sorry if mine makes little sense I'm on phone lol.

Ds knew Mumsnet would come up trumps!

Thank you.

We did 1/5 + 1/3 = 8/15 given away. So he had 28 which was 7/15. To find 3/15 you need to divide 28 by 7 and then multiply by 3 which means the bosun had 12.

12!

Probably couldn't explain my working out though...

Yeah what cola 2 said. The idea is that you need to work out what fraction of the rubies the pirate has left.

Did yr DS not know how to do it? Wot's the point of HW when the subject has not been covered??

Maths is not always about doing things that have been covered. It might be about things that aren't taught to teach pupils to think for themselves

Read your child’s Maths text book. Read a few pages on from where they are. Examples and explanations are often just a page or two further on. Check out the Khan Academy online help if you really get stuck. Plenty of maths help for all ages.