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Roz12

Posted: Tue Sep 10, 2013 12:03 pm 

Joined: Wed Nov 02, 2011 9:45 pm Posts: 118

Hi all
Help please!
Q 46 John and Ali counting on from 0
They each count on in steps of a different size
The first number that both John and Ali reach is 120
What size steps could they have been counting in?
Answer is 8 and 15
Q48
Mr Firat needs to uy posts and panels for a new fence of elngth 8.5m
The panels are 2m wide. the posts are 10cm wide.
There are posts between all the panels, and one at each end of the fence.
How many posts and how many panels should Mr. Firat buy?
answer: 4 panels and 5 posts
Q50
Mr Phillips buys an empty hanging basket for £4.00
Plants for the hanging basket cost £1.00 each.
What expression would give the total cost in pounds if Mr. Phillips buys n plants
Answer:4+n


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parent2013

Posted: Tue Sep 10, 2013 12:48 pm 

Joined: Mon Aug 12, 2013 9:13 am Posts: 452

Ans 46. It is a good word problem related to factors. “They each count on in steps of a different size” and “The first number that both John and Ali reach is 120” actually means “there is no common multiple” before they reach (common number) 120. Furthermore, “They each count on in steps of a different size” means that their numbers are different.
The logic is to find all possible factors first for 120 and see which ones do not overlap i.e. don't hit a common number before reaching 120.
(2, 60) but 2 X 30 = 60 = 60 X 1 ....so ruled out (4, 30) but 4 x 15 = 60 = 30 X 2 …….so ruled out (6, 20) but 6 x 10 = 60 = 20 X 3 …….so ruled out (8, 15) 8 x 15 = 120 = 15 X 8 is the answer (10, 12) 10 X 6 = 60 = 12 X 5 …….so ruled out
The confusing factor combination is (3, 40) which also reach 120 without hitting any common number. Wondering why that is not the answer and will wait for other members to throw some light.
Ans 48 Total length of fence is 8.5 m. You have to get a combination of panel (2m) and post (10cm i.e. 0.1m) to make a total of 8.5. But remember that there are posts between all panels and also one each at end of the fence.
Consider the most straightforward scenarios of 2 post and 1 panel i.e. PostPanel  Post 2 post + 1 panel = 2 + 2 (0.1) = 2.2m which is far below 8.5
The hint lies in the decimal part of 8.5 i.e. 0.5 which actually indicates that 0.1 should be multiplied by 5 to make it 0.5. So I’ll try 5 post which will require 4 panels.
(4 X 2m) + (5 X 0.1m) = 8.5m
Ans50
One plant cost £1.00. therefore n plants will cost 1 X n i.e. n
This can be easily understood by putting numbers. For example 5 plants will cost 5 X £1 = £5, 7 plants will cost 7 X £1 = £7 therefore n plants will cost 1 X n i.e. n (algebra)
Now to put n plants you need 1 hanging basket which cost £4.
The total cost is
“cost of plants” i.e. n plus “cost of basket” i.e. 4
Answer is n + 4
Which book are these from??


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Roz12

Posted: Tue Sep 10, 2013 3:16 pm 

Joined: Wed Nov 02, 2011 9:45 pm Posts: 118

GL packspack 2 thanks for your help


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