Q&A - P2 Math

[mother777]

HI Tianzu,


now I got the model drawing and answers correct for Q1/2/3/4/7. Thanks your hints and answers for me to correlate :). found some silly mistakes on my part and corrected them.

But stuck about the MD for Q5/6/8. Pls help with these questions (MD + soln).
really appreciate all the help from your side..

thank you thank you

[tianzhu]

Hi


You may wish to check with the teacher again.

4 years ago, they were 62 years old (four of them).

4 years later (now), the total age is 76.

I think it should be 78.

Why?

Because you add (4*4) which is 16 to 62.This gives 78.

Best wishes

PS ------ we can have 76 on condition that Adam’s brother was still" not manufactured" 4 years ago.

[metz]

3*4 = 12


12 + 62 = 74 (total age of 3 persons in 4 years’ time)

Since total age of 4 persons now is 76 =>The younger child is 2 years old now.

[tianzhu]

Hi


Assuming that Adam’s brother was still “not manufactured” yet 4 years ago, then 76 is possible.

Adam’s brother is now 2 years old.
Adam is now 5 years old.

Adam’s mother is 32 years old.
Adam’s father is 37 years old.

Total ------ 37+32+5+2 ------- 76.

Best wishes

[metz]

You are almost there for q5. Just have to divide 28 years by 2 because 2 persons are involved.


For q8, something is wrong. Total age now cannot be less than total age 10 years ago, right?

[mother777]

Hi tianzu and chamomix,


Thanks for so much ur help. Yes agree that question 8 is wrong. I will my DD to check with teacher tomorrow as must be some typo error.

Now waiting for DD to come bk Hm from school, need to sit with her to explain the concept.. Hope she can grasp it

[mother777]

hi tianzu and chamonix,


I got the answer for question 6. But bit funny because we have to make the assumption that the brother was not born 2 years ago.

for question5,
I am unable to come up with the proper model drawing and equation. pls help to draw whenever you guys are free and upload.

thanks a million in advance.

[metz]

mother777:

hi tianzu and chamonix,


I got the answer for question 6. But bit funny because we have to make the assumption that the brother was not born 2 years .

Hi mother777,

For me, it is not an assumption. It is more of a deduction based on the information given. If the total age now is 78, the question will remain unsolvable unless more info is given. (Try it). This is a tricky question, I would think.


5)\tFour sisters A, B, C and D are 24, 20, 19 and 17 years old respectively. How many years ago was the total age of A and B twice that of C and D?

[ A+B ] ......44
[C+D].......36
Age diff --->44-36 = 8

the total age of A and B twice that of C and D --->

A&B [][]
C&D []
age diff = 8 => [] = 8
C+D = 8
A+B = 16
Total age of A and B was 16 when their age was twice that of C and D.

44-16=28
28/2=14

Therefore, it was 14 years ago when the total age of A and B is twice that of C and D.

[mother777]

Hi Chamonix,


thanks for the clear explanation. yesterday didn’t get time to teach and explain to DD. today will try to sit with her and explain.

[BigDevil]

chamonix:

For q8, something is wrong. Total age now cannot be less than total age 10 years ago, right?

If Q6 is indeed 76 because Adam's brother was not born yet, then for Q8, could it be that one of them is... :yikes: ...dead??